We get a lot of calls from our great customers saying that there keys are getting hard to turn or there locks are sticking. This a lot of times is a very simple fix!! Locks are moving, working, mechanical items that need to work smoothly. There are a minimum of 33 moving parts in one single lock every time you stick your key in and out of the door!! that’s a lot of stuff going on at one time. I have been in the lock and safe industry for 15 years+ and I use WD-40 when I run across a hard to turn key and/or lock. If your lock are getting hard to turn or the key is getting hard to stick in the key hole, give it 1-2 sprays of WD-40 directly in the keyhole. Then run the key in and out of the lock several times getting all the lubricant spread throughout the cylinder. You should be fine after that. If you still have a problem, Call your local Locksmith.