Crossword puzzle clue "earth you should replace"

Earth you should replace

Street corner things that tell you you can't park here, if you should stop, where to go, etc.

Wondering "Should I? Should I not?"

"Should ___ or Should I Go"

"Should I Stay or Should I Go" singer

"Should I ___ or Should I Go" (1982 song by The Clash)

It might cause you to replace some cups

What might replace you?