Tuning Machines are probably the best guitar upgrade available to improve ease of use, and the Planet Waves Auto-Trim's are solid, reliable, attractive, and unique.
Once installed Auto-Trim's are a snap to use. Simply feed the string through the tuning post where marked, lock the string in place with a sufficiently sized thumb-wheel, and turn the tuning key as usual. Here's where you'll fall in love with these unique tuners... as you bring the string into tune, the excess string is automatically clipped off with the built-in hardened steel wire cutter. The days of impaling your fingers with short guitar wires are gone forever!
In addition, with less extra string wrapped around the post, you'll stay in tune more consistently. The 18:1 gear ratio is perfect for smooth operation and precise tuning.
Installing new tuning machines is very easy when the existing holes are large enough for your new tuning machines (look at the images for specifications, and check your instrument). However, if your existing hole is too small you may need to drill larger holes. If you are uncertain if these will fit correctly or if you would prefer to have someone with experience install them, most guitar stores will have a qualified tech who can do the job.
Note: Auto Trim tuners will accommodate a string up to about 0.65".