People use this phrase to complain about someone not helping with chores like cooking, cleaning, yard work, etc.:

It wouldn't kill you to help out around the house sometimes, you know.

This means "You can (and should) help with the housework."

You can also phrase your complaint as a question:

Would it kill you to straighten up your desk every now and then?

You can use the phrases for other activities like exercise too:

It wouldn't kill you to do a few situps.