When to replace points

[BILLF/TRF]

I have a new Mallory dual point distributor and it is running fine. I remember when I was young my Dad would periodically have the garage do a "tune-up" which would usually involve replacing plugs, points and condenser. I don't recall how often he did that and if there was a reason for it? In my '36 coupe (59AB engine) I only put on about 1,000 miles per year and wonder if I should just wait till the car runs rough or just replace them every year or two?