A little comment on tooth count on blades as I'm cutting aluminium right now.
With any material go with the largest tooth count you can use. The main determining factor on the number of teeth is material wall thickness. The thinner the material the more teeth required.
The second factor is material Aluminium requires less teeth if possible because of clogging of the teeth which causes binding in the cut with all sorts of negative results. Finally feed rate, harder materials require high feed rates (higher pressure) so that the teeth can bite and don't wear out the blade, softer materials (aluminium) require slower feed rates (less pressure) just enough to so that the blade can clear to chips without binding yet still cut.
This took some knowledge from manufacturers of the blades and experience (destroyed blades) to figure out this simple knowledge.
Know rarely need to change blades because most of the issues are resolved.
What do I cut, Aluminium, Stainless Steel, and steel in that order same blade for all, only change happens with thin walled cuts of any material.