The area where caulk is replaced needs to be perfectly dry prior to applying new caulk.
If I am recaulking your shower, please, if possible, do not use the shower for at least 12 hours before I come. Caulk requires about 48 hours to fully cure.
NO MATTER WHAT, after I am done, do not get the area wet at all. If there is any moisture around new caulk, it will not cure, and I will have to come back another day. I can not guarantee that if I need to return, it will be the next day, as I usually have back-to-back jobs. Also, I will charge for my time to remove damaged caulk and reapply it.