Caulk is an important barrier against water and air leaks but it does not last very well.  If the caulk is dried and cracked or if it has come loose you will need to replace it.  When repairing caulk clean all of the old caulk out and clean the surfaces.  Use a hair dryer to make sure that the surface is very dry before you apply caulk. If you are dealing with a gap of 1/8” or larger, we recommend that you use backer rod before applying caulk.  If you are not experienced with a caulk gun, it is a good idea to run a piece of tape along either side of the caulk line, leaving enough room for the caulk to make good surface contact.  Once you have smoothed the caulk you can pull the tape and have a very clean professional looking caulk joint. With the grout you will be checking for a few things. First check to make sure that it is clean.  Dirt and grime can discolor grout.  Often when grout is dirty it will take on more of a modeled look.  Using a cleaning solution scrub a small section of grout to see if it changes color.  If it does it will need to be cleaned.  Depending on how dirty it is, this process will determine how you will need to clean it.  There are specialized, often toxic, grout cleaning products.  Almost always the most important ingredient in cleaning grout is elbow grease.  Once the grout is clean you can check for loose and cracked grout that will need to be removed and repaired.  If the grout does not seem to be overly dirty or in need of repair, check to make sure that the sealer is still working.  If water beads up on it, the sealer is working.  If you have to scrub the grout, clean it or if water did not bead up on it you will need to reseal it.  There are many different sealers on the market. While we specify penetrating grout sealers in new construction they are usually not a good choice for resealing because previously sealed grout will not allow absorption.  In most instances we recommend an acrylic surface sealer for regrouting. Read the instructions carefully and follow all of the recommended steps accordingly.  This is not difficult but attention to detail is important.