Post bathroom remodel question?

Question:About 4 weeks ago I had a complete bathroom remodel done, everything demo'ed and all new put in.

Is the grout supposed to get darker when the shower is in use? The old tile was not like that, also I keep discovering tiny holes in the grout, that weren't there before.
Is either of these something to worry about, or will it cause me problems down the road?

I ended up having the contractors from hell, I had to double check everything thing they did, for 3-4 days in a rowI had a punch out sheet daily with between 15-20 items listed that needed to be done and/or corrected.
Are the things I mentioned regarding the grout just more to add for them to fix? I don't think the grout was sealed, and I don't know if that is part of the job or an add on, does anyone know what the industry standards ares?

Thank you in advance.

Answers:
grout was probably not sealed, an easy fix is using a tub n tile cleaner then go over the grout lines with Tile Guard Tile Grout Coating by Homax. It made my 80 year old bath grout look brand new. About 7.95 4oz bottle, enough to do average bath.