For my new build, I've picked up 80% of my new electronics used. I don't see the point in getting a new PM1 module (for example) when I can buy a used one for a fraction of the price and have the same result. Anything that requires high maintenance to keep optimal (pumps, skimmers, etc.) or has an expected operational life under 2 years (heaters, bulbs, etc.) I avoid buying used.
I'm looking to save some money and willing to accept some risk of unexpected failure, but there's a limit. That would be my suggestion; determine what level of comfort you have with accepting risk and use that as a guide (assume you won't have warranty coverage for used equipment - sometimes you do, but safer to assume not).
I'm looking to save some money and willing to accept some risk of unexpected failure, but there's a limit. That would be my suggestion; determine what level of comfort you have with accepting risk and use that as a guide (assume you won't have warranty coverage for used equipment - sometimes you do, but safer to assume not).