I am currently studying magnetism as a part of AP Physics 2, and what confused me was that a Tesla was the unit for magnetic field strength(which decreases with distance) but it was also used to measure the strength of magnets. Why is this the case? Is there not another metric that could be used to measure the total strength of the magnet? Also, when the strength of a magnet is given in Teslas, at what point from the magnet is that number derived?
It simply means the strongest field generated by a magnet, wherever that may be. For a bar magnet, the maximum field is typically going to be right at the surface of one of the poles. For a horseshoe magnet, the maximum generally occurs somewhere roughly in between the two poles.
The maximum field is a useful measure, because it tells you what kind of local fields you can produce with the magnet. If you need a 10 T field for an experiment, an 8 T magnet will not suffice. However, with a 10 T exterior field magnet, there will be some places where it's field is only 8 T. Making strong magnetic fields is fairly hard, but moving a sample to the particular point where the field is what you want (and in many cases, that means the larger the better) is comparatively easy.