expression, godan verb (-mu)
go on a fool's errand; go in vain
Used when a trip or visit turns out to be pointless, often because the purpose was already lost or the person was absent.
わざわざ行ったのに、店が閉まっていて無駄足を踏んだ。
I went all the way there, but the shop was closed and it was a wasted trip.
事前に電
If you don't call ahead to check, you'll end up going for nothing.