When to freshen engine

It all depends. If you run no air cleaner or an open scoop, live in a dusty area, have dirt pits where you race, things may get worse faster. Around here a "local" bracket car might only get 250-300 runs a season. IMO it's great to have the oil looked at, but I also like visual inspections. Especially given the aluminum rods.
You mentioned the rods getting sent out - If you're breaking down the rotating assembly... mic the bores. If it's still round and square, I'd hit the bores with green scotchbrite on a flex hone while it's apart to clean out the hone pattern and then file fit new rings.