Choosing yours
More than any other tool, a ratchet can last you a lifetime. Quality ratchets can be serviced inexpensively therefore should never degrade. Sockets are interchangeable because they’re all standard. Buy the finest ratchet you are able, even if you get inexpensive sockets to begin with.
Socket release
Sockets will be held onto the ratchet using a little spring-loaded ball on the side of the square travel. After applying a lot of push, I’ve typically found sockets get trapped on the drive and the only path to have them off is usually to hammer 
the ratchet on to the floor or even hold it in a vice. Good quality ratchets add a button on the back which effortlessly pushes off the socket while you are ready to Ratchets Wheel release it.
1/4 inches – Used for smaller sockets and precision work. Beneficial for dismantling individual pieces on the bench.
3/8 inch – The center sized, and for me, most useful size for standard use on an automobile. A 3/8″ travel can drive sockets of all sizes. It is big enough to use quite a lot of force, but not really too big to fit into tight spaces
1/2 ” – 1/2″ sockets are usually employed for nuts and bolts from around 10mm and up. A 1/2″ drive socket can apply enough power to undo all nuts on an automobile.
Additionally, there are 3/4″ and 1″ ratchets but these are used on trucks, tanks and commercial machinery.
Tooth count
Inside a ratchet you will find a toothed wheel which lets it freely rotate as you tighten the nut. Each just click you hear can be a tooth passing the ratchet. The more pearly whites there are, the less movement is needed on the return stroke. A ratchet with 75 teeth will work considerably faster when compared to a 32-tooth ratchet. Making great tooth-counts requires top quality engineering and developing, so as an over-all guide the better top quality tools will have a higher tooth count.
Drive sizes
socket-drive-sizes
All ratchets accept sockets by using a square travel and mostly there are three sizes of drive. All around the community these sizes are given in inches – even when the sockets happen to be metric.