It depends on what you're torquing.
What's the application? What force are you looking for?
Torque is force times distance.
In US units we usually say the distance first (inch pounds or feet pounds).
In SI units we usually say force first (Newton meters).
12 inch pounds = 1 foot pound.
With any tool you don't want to be measuring towards the end of the scale. I would not use a 0-100 ft lb torque wrench to measure 15 in lb (1.25 ft lb) on a receptacle, for example.
You can also buy them calibrated to a specific torque if you're looking for the same torque consistently.