If grout is in between 2 different materials, say between stone and tile or wall and tile, then the 2 different materials expand and contract at different rates. There's no way to avoid this and that's why caulk is used more often in these locations. If you have grout cracking and crumbling in other locations such as the middle of a run of tile, then it's possible it wasn't sealed? Cracking of grout is unavoidable, but it depends on how bad. I would try re-sealing and see how it goes.
15 months ago
Grout only cracks when there is movement.
This generally only occurs when the tile is laid poorly, the substrate is weakened due to water damage or the building has been shifting.
15 months ago