Regrout Master Bath Shower
 

Not sure why your shower needs to be regrouted, there are much less costly options and sone DIY options.

Our grout was not originally sealed, I did the sealing myself with a product that was supposed to be good for "20 years". Well that did not work, so after several years I came across "Grout Shield" this is a paint like product, and comes as a complete kit, cleaner, tools, and colored sealant. We chose to keep the same color as the original grout, and they match it so close that I actually missed a few areas, which I found the next time I mopped the floor. I just touched of the missed area. I think we are going on 5 years and ground looks very good, but does still need an occasional cleaning in the heavy traffic areas.
Lowes sells similar Mapie products, but I have never used these.
My point, I did the entire tiled area of our house (no bedrooms or closets these were carpeted), and both bathrooms and the shower, took around 2 weeks 3 or 3 hours every other day, and probably save hundreds to a couple of thousand dollars. The kit was $60.

Now if your grout is actually cracked and falling out, then the above is not a good solution, however my stepson who has done tile installation indicated grout removal and replacement is a time consuming and dirty project.

I hope this helps, feel free to send a PM if you would like to discuss further.

Do yourself a favor and get rid of the tile. The grout problems will never end. Check out JettaStone or Central Florida Bath. Looks great and you're through from then on.

The Grout Specialist
 

I had mine re grouted in 2018 by The Grout Specialist 352-735-5218. Call for an estimate. The lady pulled out all the old and re grouted. $185.00 at the time. The grout is still in good condition. She spent the time (about 3 hours on-site) and did it right. Yes I could have done it myself but the original guy did not do it right and he was a tile guy.

All About Grout

All About Grout and More, Tile & Grout Installation, Cleaning, Sealing, The Villages

Glad you had a good experience. When All about Grout did our grout project, they used the wrong color, so it did not match with the grout that was not being replaced. I asked the owner why they did it this way and his response was, "that was the only color I had with me".
When he was out doing the bid, he should have observed what color of grout to bring for this job. NOT HAPPY...