Updated: Nov 3, 2021
To maintain the accuracy of your trainer you will want to calibrate it once per week or so with a spin down. This can be done in Zwift or via your trainer's utility app. The Tacx trainers are an exception as they don't need calibrating.
The other piece to maintaining your trainer is to make periodically make sure that the firmware is up to date. This you can do through your trainer's utility app. Keeping the firmware up to date will improve the trainer's accuracy and performance on Zwift.