Well, there are a lot of manufacturers so the answer will depend on what you choose. In general, though, you need the right numbers in the right sequence...not just the numbers in any sequence. I wouldn't worry about someone bothering to use fingerprint powder, but I do know that -- on some keypads -- the numbers on the buttons that are used can wear off after a while.

It's nice to try and "outsmart" the bad guys but if they want in bad enough, they'll simply break a window. Put your money into a reputable security system.

It depends whether the lock is electronic or manual. I have the manual type - no batteries - and the order the numbers are punched in does not matter.

I think the idea of searching for fingerprint oil is pretty far-fetched.

We got a schlage keyless deadbolt like this

http://www.amazon.com/Schlage-BE365VCAM619-Camelot-Keypad-Deadbolt/dp/B000NJJ1MQ/ref=sr_1_3?s=hi&ie=UTF8&qid=1327115690&sr=1-3

it is a little touchy and you might have to reenter a few times, it also turns with a little more pinch effort than I like. It had the best reviews when I selected it. I'm sure you can't get in with anything but the real code. I'd prefer to have found one that is self locking but I couldn't get everything I wanted in one lock. Do a deadbolt is you are worried about security. A credit card can open a regular door lock.

I can't really complain but if I had to compare it with my chamberlain keyless garage door opener I'd say that chamberlain is less fussy, and requires no pinching- just push the button, also contractors are familiar with chamberlain and seem a bit afraid to use the newer looking schlage.

as far as your oily finger question. we've changed our code several times after certain deliveries, and contractors were done ( or fired) , and changing the code would eliminate an overuse "tell" on any certain keys.

"and changing the code would eliminate an overuse "tell" on any certain keys."

Only if you change the combination to use other numbers.