TIL a wrinkle in the carpet can mean a dip in the floor
On my last install, the carpet got a wrinkle that wouldn't stay put. I found a low area in the subfloor causing the problem. Filling it with leveling mix fixed it for good. Now I always use a straight edge to check before I start.
Honestly dylans23, I see floor dips as one of the easier fixes down there. Sure, they're annoying, but leveling with self-leveler or a mud job is pretty straightforward. The real headaches start with horizontal wall cracks or finding active mold behind the paneling. Those problems have way steeper learning curves and can turn a simple job into a total mess.