Choosing yours
More than any other tool, a ratchet can last you an eternity. Quality ratchets could be serviced inexpensively therefore should never degrade. Sockets happen to be interchangeable because they’re all standard. Buy the finest ratchet you can afford, even if you buy inexpensive sockets to begin with.
Socket release
Sockets will be held onto the ratchet using a small spring-loaded ball privately of the Ratchets Wheel square travel. After applying a lot of push, I’ve quite often found sockets get trapped on the drive and the only path to get them off is to hammer the ratchet on the floor or even grip it in a vice. Good quality ratchets add a button on the back which smoothly pushes off the socket when you are ready to release it.
1/4 ” – Used for smaller sockets and precision work. Valuable for dismantling individual components on the bench.
3/8 inch – The middle sized, and in my opinion, most readily useful size for basic use on an automobile. A 3/8″ drive can travel sockets of most sizes. It is big enough to use quite a lot of force, but certainly not too big to match into tight spaces
1/2 
inches – 1/2″ sockets are usually employed for nuts and bolts from around 10mm or more. A 1/2″ drive socket can apply enough power to undo all nuts on a car.
Additionally, there are 3/4″ and 1″ ratchets but these are used on trucks, tanks and professional machinery.
Tooth count
Inside a ratchet you will find a toothed wheel which enables it freely rotate as you tighten the nut. Each just click you hear is usually a tooth moving the ratchet. The more tooth there are, the less movement is necessary on the give back stroke. A ratchet with 75 teeth will work considerably faster when compared to a 32-tooth ratchet. Making great tooth-counts requires quality engineering and manufacturing, so as an over-all guide the better top quality tools will have an increased tooth count.
Drive sizes
socket-drive-sizes
All ratchets accept sockets using a square travel and mostly there are 3 sizes of drive. All around the universe these sizes are given in inches – even though the sockets happen to be metric.