Only do it once a week, and usually only one way, but it’s 45-50 miles. At which point it’s basically a ride not a commute. Sometimes drive half way and do 26-30 each way.
18 each way is a great distance. Short enough to do every day (I’d probably do 4 out of 5 to bring clothes in without a bag), but not so far it’s either a real struggle to motivate yourself or totally destroy yourself.
I miss being able to commute by bike every day.
But this is in chat, so dunno if you mean time, rather than cycling specifically. In which case mine takes c2 hours each way by train. But we did this recently.