Cracks in floor tile grout
 

Just moved in house- 3 years old. Have noticed cracks in floor tile grout. Does anyone else have this problem and is there an easy way to fix this?

Usually, grout cannot be repaired, only replaced. The easiest way is to remove the old grout, replace with as close a match as possible, then when cured, stain all the grout (new and old) with a stain/sealer.

MY house is 6 months old. I have grout cracks. Will be fix under warranty.
It is caused by the settlement of the foundation. In my previous house in TV, I had grout an tile cracks. (fixed under warranty) That's why the builder leaves extra tiles and grout.