I have my car and truck serviced at dealer. It doesn't cost me any more for them to change oil/filter. While there they check about 20 things, includint doing a battery conductivity test.
They tell me long before battery dies, it having a problem.
So I purchased a battery conductivity tester. Gave my old battery load tester to my brother-in-law. IMHO load testers are old school and not very accurate.