I am about to start the regrouting of my shower tonight with the removal of the old grout. I am hoping to be regrouting by this weekend and I have a few questions to help me out if possible.

Do I have to absolutley remove all of the grout (it goes to the ceiling) or can I leave a row or two at the top or just not dig as deep so the grout will match?

I am pretty sure I am supposed to caulk the corners and where the tile meets the bathtub but someone said to caulk first and then grout but that does not make sense to me. Any suggestions?

What do you recommend cleaning the tiles with once I have removed the grout? I am concerned with the cleaner dripping into my dining room like water has been and this time leaving a bleach stain.

How long do I wait after cleaning and before regrouting?

You do caulk at the seams and corners but do not try to grout over the caulk, just up to it. The more grout you remove the better off you'll be and the longer it will last. I recommend a pre-mixed stainproof grout. Force it into the grout lines with a hard rubber trowel swiping on an angle to the seams. Allow to set up for about 15 minutes and wipe with a well dampened sponge turning and rinsing regularly. Wipe again after an hour. Tomorrow wipe with a vinegar water mix and buff. Do not use the shower for 72 hours.

You will never be able to get all the grout out, but you should try to get as much as possible. You can clean the tile with a vinegar water solution before the old caulk and grout is removed. Then you should remove all of the caulk and grout before you regrout (http://www.precisiongrout.com/our_work) and re caulk. You can promote the drying process with good ventilation but do not over due it as it may cause cracking in the grout. Drop me a Pm if you have any more questions...