Product review (5 stars): Why Buy a New Dryer, When You Can Fix It With This Inexpensive Part?
My 25 year old Whirlpool dryer started blowing cold air not because of lint buildup or any real air system overheating issue, but rather because after all of those years the press-on electrical tab connector got a little loose, then a little hot, then a lot looser and then a lot hotter until the connection's heat melted the plastic housing on the High Limit Switch causing the wire to fall off.

This very reasonably priced High Limit Switch corrected the problem and now the dryer is good for another 25 years.  In fact it should last longer (with a belt replacement no doubt) because this time I soldered the press-on tabs directly onto the Switch, so that over heating at the power connection will not occur again.