Since this question (mixed in with others) didn’t get any comments, I’ll try it as a stand-alone question.

200K+ on the factory heater-a/c fan and resistor, and they’re still working just fine.
I see enough comments here to know they do eventually fail.
However aftermarket replacements can be short lived.

Am I better off to replace them while I have the heater box stripped, or is it a toss up as to which will last longer (original or aftermarket)??

STANDARD MOTOR PRODUCTS RU109 {#4720278, 68004241AA} Info
I'd get this resistor. I'll have to look around at blower motors. I don't know what year your truck is. This is for a 98 1500

Mopar 0501 5866AA, HVAC Blower Motor

by Price: $125.83 & FREE Shipping

• Genuine Mopar OEM product

I couldn't find an AC Delco or Standard Motor Products blower motor. I wouldn't buy a cheap one. I would definitely replace the resistor, and probably the motor. Then the whole system is new again.

Yup, mine’s a 98 1500... pre June so not 98-1/2.

Those parts should fit then. I was hoping to find a good quality blower for $40-60.

Don't feel obligated to replace these when the dash is out. They are easily accessed when the dash is in place. Feel free to wait til they need replacement.