And just for clarity, I replace my DI once TDS hits 1, I might make a batch or two with that but I try to keep DI on hand when it creeps up. I'm around 8-10 TDS after RO.

It also doesn't hurt to flush out the lines after the membrane prior to making water. Depending on your kit, you may have a valve to supply RO water for drinking. I sometimes open this and flush the lines into a pitcher so I don't get that water into the DI. I don't do this very often, though I mean to.