5 minute timers for activity transitions. I started using them as a visual aid for when bath time would end, now she asks for them at every transition - before going to school, before leaving the park, before eating dinner, before getting ready for bed.

And while sometimes we want something done right now, her request for a 5 minute timer is a great check on our own expectations - are act of the things that we're asking so critical as to impose our will on her and deny these 5 minutes? Pretty much never.

It also works great for when we need 5 minutes - we can ask for a 5 minute timer before joining her for play, etc.