/diy/ - Do It Yourself

Hey guys, first time homeowner here so bear with me.

2016 house, we bought it new construction. Master bedroom and bath is upstairs. Whenever someone takes a hot shower or bath in the winter like right now (SW Texas, so not below freezing) I hear this clicking or ticking coming from the drain pipe that goes straight down the wall to the sewer main. PVC piping so obviously it's the pipes expanding in the heat, but I have some concerns:

1. How damaging is this for cold pvc pipes to expand and contract like this? What are the long-term effects?

2. We basically don't run our heat at all during the winter. Where we are in TX it rarely ever goes below freezing, maybe 5-10 days of the year max. Most of our winters are in the 40s-50s. So most of the time the indoor temp in our house is in the 60s, occasionally going down to the high 50s. Since the house is new construction it's well insulated and sealed up tight, we have a radiant barrier and blown insulation in the attic and I saw they put in fiberglass insulation in the exterior walls so those drain pipes are being somewhat insulated. Is us keeping the heat on 55 going to negatively impact the pvc because it's going to be colder by default and expand contact harder?

Again please bear with me but I'm totally new to a lot of this stuff and I'm really paranoid that basically everything I'm doing is destroying this house. Appreciate any wisdom from you guys.