If you don't live near a dealer who can test tubes for you a tube tester is not a bad investment. That one looks interesting but a bit limited perhaps look into what else is out there?
Tube Tester Option
https://www.ebay.com/itm/233953776139?chn=ps&mkevt=1&mkcid=28
With all the money I "gamble" on audio, maybe I should just buy this and try it.
With all the money I "gamble" on audio, maybe I should just buy this and try it.