Starter Battery Condition

Mate

take it to a battery place and they will test it 'under load'.

The best way to test a starter battery is on a carbon pile battery tester...most good battery shops and some auto electricians will have one...it allows test under a variable heavy load.

The are simpler battery testers that apply a fixed load often refered to tong testers, because the early ones looked like a pair of tongs with a meter at the hinge.
I have one of these that give only a fair indication.

Bottom line if the battery is more than 2 years old and it is failing to crank with vigor on a cold morning...its hardly worth the effort of heaving it onto a bench to test it....it will be below spec.

cheers

Sometimes a low tech approach is OK too!

Is your battery a sealed, or unsealed type?
If you have an unsealed battery, you can unscrew the caps and check each cell with a simple hydrometer. This will display the specific gravity of each cell and if one or more are failing.