It depends on my key ring, but lots. Frequently I have two key rings at once. My daily key ring has car keys, house keys, tool box keys, workshop keys, and parents house keys (multiple bitings), while ...
Key rings get exceptionally frustrating when you have difficult keys that don't want to come off. (I'm looking at you, car keys!) A smarter ring, called FREEKey, makes key removal a whole lot easier.