Locking tuners... ahem.
If folks would learn how to string up correctly... locking tuners would never be needed.
With practice, you can string up with 1-1/2 wraps on the post, or a little less on wound strings. If you do it right, they will not slip.
may I humbly suggest, again, that folks go over to www.frets.com and have a look see at the correct way to string things up!
A potential problem when stringing, are wraps on the post of the tuner, which will give you some grief as the wraps stretch and contract as you tune.
Which brings me to..... when tuning, we learn to "tune up". Thats easy. But what is not usually taught, is to radically tune down before tuning up. In that manner, you've stretched any wrap on the post. If you overshoot, go way down, then up again until you have it right. Going down "just enough to hear that the string is flat" will often result in problems.