There is a crack in the plastic connecting to the wheel does it need to be replaced?

Could you take a picture of the part in question please and post it on here using the add image link? At the moment I'm not sure which area you are looking at that could be cracked.

Okay, those are there to keep dust and crud off the strut area. The rear ones are generally something added after purchase and come as a split item that is added on unless someone added solid ones with replacement shocks. The front ones are a bit more complex as those need to have the struts removed and disassembled to replace them. In both cases they provide some protection of the sliding ram and seals but they are not a critical item. I would likely say you can wait until the shock or strut requires replacement and do it all then.

You're welcome.