Product review (5 stars): Dryer wasn't drying well - This did the trick. Here is what to look for
Over the past few weeks my dryer started getting slowly worse, requiring 2 then 3 rounds to dry a single wash. I first cleared out the vent line to make sure that it wasn't obstructed, but the problem persisted. I opened up the unit, removed the drum, and found that the burner was cycling off way too quickly (like after 10 seconds).

I removed the cycling thermostat and checked its operation as follows: I put it in a frying pan (sensor side down) and heated it up and kept monitoring continuity with a multi-meter and temperature with a laser thermometer. It was kicking off way before 155 degrees so I knew that it was the issue. I replaced it with this one and the dryer is now working fine. I visually confirmed that the burner is staying on for longer. A few tips:

1) Youtube is your friend. I learned all of this in an hour or 2 on youtube.
2) When testing burner cycling, do it with a load of wet clothes in the dryer and through the peep hole. No need to take it apart before that.