Logic analyzers. Just applied for a Saleae hobbyist discount code. Never owned a logic analyzer and was looking at DSLogic and Saleae. The DSLogic plus seems to be more capable on paper, but Saleae seems to have the much nicer & better supported product?
Right now I'm using my Siglent scope's decode function to occasionally look at (usually serial) communication pins when tinkering with stuff i try to hack.
Any other recommendations to look into?