Preparing for a XC : Bathroom Breaks

I've mastered fuel management now the hardest part. How to manage mine and
my wife's bathroom breaks. Our trips are typically 3 to 3.5 hours but our
blatters don't always make it thus forci6ng a stop. Thats a big 30 min
addition to the trip. On my last filight I filed two flight plans and then
called ATC to open the next flight plan when we felt we could make it all
the way without the stop. Seemed to work.

Any suggestions on preflight preparations that have worked for others ? No
coffee before the flight ? No liquids xxx hours before leaving etc. etc.
Sort of like preparing for an operations.

Thanks.
Holding it in