Is there any "Rule of Thumb" to change from mono to braided line on older reels that are at least 15-20yrs old. Recommended or not?

As long is it’s been maintained it doesn’t matter what kind of line is used regardless of age. 
 

 

 

 

Mike
 

 

Roger that Mike.

4 hours ago, Gfd63 said:

Is there any "Rule of Thumb" to change from mono to braided line on older reels that are at least 15-20yrs old. Recommended or not?

Use a mono backing.  That's about all I can say.  I have a few reels that are 30+ years old, and a pair that are 50+ that still get used.  I either have braid, or have had braid on all of them.  The only real difference I notice between them and newer reels is newer reels tend to have textured spools so that the braid doesn't slip around the spool.  The older reels tend to have smooth spools, and benefit from a layer of mono to keep the braid from slipping.