...would use non-protected if someone would give me some basic rules on how to keep them safe. Thanks!
This may not be a comprehensive list, but I'll have a go at starting it.
Never:
1. Over charge, voltage or current.
2. Over discharge, voltage or current.
3. Exceed temperature ranges. There are separate ranges for charging, discharging, and storage.
4. Leave a cell deeply discharged for long, then try to charge it.
5. Be stupid - burning, denting, nailing, shorting, eating, etc.
Protection circuits protect against the first three (except storage temperature). The rest are up to you.
Using a proper, quality charger should protect you during charging.
One of the ways cells get over discharged is by having two or more in series that are mis-matched or imbalanced. If this happens, the weakest or least charged cell will reach full discharge, and the remainder will continue to push current through the load, and the fully discharged battery. This will over discharge it, possibly even putting a negative voltage on it. This is really dangerous. That's why many people say NEVER run unprotected cells in series. A device that operates on a single cell will usually stop working before the cell is dangerously over discharged, which is why many people feel quite safe using unprotected cells in single-cell devices. However, this may depend on you knowing the cell is discharged, and removing it from the device and charging it.
If you are really interested, go to batteryuniversity.com and be prepared to spend some time reading.
Oh, and I've been happy with batteries bought from Batteryspace.com and Liionwholesale.com. I also bought some Keeppower cells on Amazon that I think are genuine.