Product review (5 stars): Even easier than changing wall plugs and switches!
Had the heater/defrost unit go on same fridge in 2004.  Watched as service tech (Sears) did the replacement & saved the paperwork.  Parts: $63.00  Labor: $146.00 (including $60 service call).

Fridge defrost heater started acting up last week (10 years almost exactly).  Purchased new assembly & installed it myself.  Took longer to defrost the freezer coils with hand-held hairdryer than it took to do the actual install.

$60 part vs. $800-$1200 new fridge ... no brainer!  Won't last as long as my 60+ yr. old General Electric fridge but should last as long as I'll ever need it!