The best defense against these tile problems is to keep your shower sealed with tile sealer and daily rinse the shower thoroughly with a handheld sprayer. Make sure spray all walls and allow all soap bubbles to rinse down the drain.
For aggressive cleaning, avoid using chlorine "bleach" or other harsh chemicals because they will whiten your grout lines and damage the grout. Use a neutral pH cleaner on a regular basis. For periodic cleaning, you may use a vinegar & water solution.
If the grout lines bead up when water touches it, then it is properly sealed; otherwise allow the shower to dry and apply sealer.

If you are interested in having us clean and reseal your shower, Call us and we'll schedule a consultation to restore your shower to a beautiful experience again.