Replying again, in the right thread this time.

You don’t have a simple option to leave a transponder turned off. Once installed you are required to use it in *controlled airspace*. 14 CFR 91.215....

On Thursday, May 9, 2019 at 5:10:06 AM UTC-7, Jonathan Foster wrote:
On Wednesday, May 8, 2019 at 10:08:20 PM UTC-6, Darryl Ramm wrote:
On Wednesday, May 8, 2019 at 8:36:37 PM UTC-7, wrote:
I have a trig transponder (no ADSB yet). This transponder is not legally required in a glider. So, do I still have to get the transponder checked every two years per 91.413?

https://www.law.cornell.edu/cfr/text/14/91.413

It appears so to me, but am I missing something?

Yes, there is no difference here between gliders (and other transponder partial exemption aircraft) and a VFR powered aircraft. It is clear in the regulations.

This may be a silly question if at the end of two years you decide not to use the transponder anymore but leave it in your panel always turned off. Would you still legally be required to have it checked?