The "flash" in the title means that the devices utilize a type of flash memory that can be written on to and erased numerous times. They are great for TRANSPORTING files from one device to another. They are NOT meant to store files long term, as in being a "backup" device and should not be used as such.
USB flash drives come in all sorts of shapes and colors. There are SLOW ones that are a USB 2.0 standard, and FASTER ones that are USB 3.0. There are some that have only 2-4 gb memory, but others that can go up past 128 gb memory.
Maybe one or two. Since you are only using them to temporarily hold the files that you are transferring from one computer to another, one flash drive is all you really need.
Try to keep your files in one centralized and organized location. Using a "Cloud Drive" is one method to centralize your files. Another is to use your computer and then backup to an external hard drive.
Never use your USB flash drive to store your primary files on, or to backup to. They have what is called "volatile" memory, meaning erasable. One day you may find your files all gone. Flash drives have a limited lifespan, said to be up to 10 years, but in practice, probably closer to 5 years. The more you use the USB flash drive, to read and write files, the shorter the lifespan. The older they get, they are more susceptible to to file corruption, which you may not recognize right away.
1) USB 2.0 is fine for PDF or Word type files, unless you have a gigabyte or more of files to transfer.
2) USB 3.0 is BEST for larger file types like with photos, audio, or video type files.
3) USB 3.0 will transfer files from computer to flash drive TEN times faster than USB 2.0
Now for the "bad news" about either version 2.0 or 3.0 USB flash devices. The interface, which is called a "Type A" interface is quickly disappearing. More computers are coming with USB-C type connections, rather than the older Type A. If you are going to STORE information on them (which you shouldn't), one day you may find yourself unable to access the files on them. Remember the common floppy drives that came with computers? They disappeared 20 years ago. Any information stored on floppy disks is basically lost.
Don't worry about using your older USB flash drives for temporary storage. As long as the computers still have that Type A interface you should be fine. There are also cables that have a USB-Type C connector on one end, and a USB-Type A on the other.
1) 8-16 gigabytes of storage should be MORE THAN plenty for a USB flash device.
2) Remember that these flash devices should ONLY be used to transport files from one computer to another. They should NOT be used to store information on them.
1) USB 2.0 - 16 gigabyte flash drives will cost about $4 per flash drive. This standard has been around since the early 1980s and is now considered old technology.
2) USB 3.0 - 16 gigabyte flash drives will cost about $5 - $10 per device. This standard emerged about 2009 and transfers information TEN times faster than a USB 2.0 flash drive.
3) Consider this. Buy a 1 terabyte (or 1,000 gigabyte) USB 3.0 HARD drive for about $50. That is the equivalent of about 62 16 gigabyte flash drives which would cost you around $500.
4) Ask yourself the question, "Should I pay $50 for superior storage OR $500 for inferior storage media?" Just FYI, a 4 terabyte USB 3.0 hard drive is only twice the price ($100), making it a better deal.
5) In general, the external USB Hard Drive is used for the backup of your files that are centrally organized on your computer's hard drive.
Use your brand new flash drive ONCE and the flash drive will retain information for about 10 years.
Use the device frequently to read and write data, and you can expect about 3-5 years of use before data integrity becomes a big consideration.
"LOST.DIR" on Your USB Drive?
That folder USED TO BE a folder filled with files that have become corrupted on your flash drive. That folder information you were storing is now GONE. (Hope it was backed up somewhere else!)
If you run across this issue, remove what good files you have on the USB drive and move them to another drive. Reformat the USB flash drive before using it again.
Only a year or so after the USB 3.0 Standard came out, a small group of researchers found major flaws in the underlying coding of USB devices. These devices were designed to work across multiple platforms, but unfortunately that brought huge security risks with it. The susceptible code was kept "under lock and key" for many years until information leaks occurred over time. It is now a platform for malware hackers to begin implementing their malicious activities.
Malware programmed right into the device's hardware can NOT be scanned for by even the best antivirus software since the malware resides INSIDE the hardware, not in the storage memory.
"FREE" flash drives are never free, and as many people have found out, these devices were loaded up with malware and sent out in the mail. Hackers, and Chinese, right?
Question: "Should I ever use someone else's flash drive?"
Answer: You never know where that USB device has been. Yuck!@! That flash device could be laden with firmware malware, ready to quickly infect YOUR computer. Every computer the USB is plugged into will become infected. Not my type of fun.
All security folks recommend tossing out USB flash devices of unknown origin. I would NOT even peek at what is on the device.
Don't share your USB devices with friends, nor allow them to put their USB flash drive into your computer.
BE VERY CAREFUL WITH HOW YOU USE THESE DEVICES!!! This is NOT going to be something that can be fixed with time. USB-Type A standards were compromised from the start. Newer USB-C standards are becoming more popular and are much faster as well. The extent of security built into this standard will be seen as time goes on.
#1) Save your files right to your cloud drive from anywhere. Most people have a Microsoft, Google, or Apple email account. With these accounts, you have associated "cloud storage" which you can access through any browser. Simply log into your particular cloud storage and upload your files to this cloud storage. Once you know how to do this, it is a very simple matter to upload or download files from cloud storage.
#2) Save your files to a USB Hard Drive. These are small portable hard drives that have storage capacities upwards of 2-4 TERABYTES of storage. Using these drives also allows for keeping all your files on one drive creating a centralized file system. They are also more resistant to sudden data loss by electrostatic discharges like USB Flash Drives have problems with.
These "clouds" are basically large "server farms" where data can be securely held and kept safely backed up.
There are many “Clouds” to choose from with probably the most common being Dropbox, Google Drive, Microsoft OneDrive, and Apple iCloud Drive, however there are many others as well. The cost is minimal, 99 cents/month for 100gb of storage, and on up the tiers to $10/month for 2 terabytes. Each service will vary, so you will need to explore what plans they have.
Having your files stored in a "Cloud" offers you a way to keep all your files synchronized across multiple devices (iPads or tablets, Laptops, Desktops, etc). When a file is uploaded or changed on one device, all the devices connected to your "cloud account" will then be updated to reflect the current file changes.
Most of the major "Cloud Drives" offer a desktop app that will install and integrate into your desktop browser (File Explorer in Windows or Finder on Macs). This allows you to organize, move files, or create folders in your "cloud drive", just as you would do with any of your files on your hard drive.
A file in the "cloud" is available anywhere you may be, such as at the Family History Library, "on the road traveling", and so on, as long as you have internet of course.
What if your computer hard drive suddenly dies? Don't worry, your files are still stored on your cloud drive. Replace your hard drive, reinstall your "cloud's" desktop app, and the files will download back to your desktop. This should NOT be your only backup strategy though!!