Detriot Lakes. MN,(cool season) well, let's say you have a K blue lawn. Mostly sun-low to moderate thatch. 4lbs N per year is recommended for best results.
A shade turf with creeping red fescue should top out at 2lbs N/1000.
Mixed variety lawns can vary with soil composites. Sandy soils can leach nutrients, so requirements can be higher. Clay soils can hold N-(lots of P)-K, so requirements can be lower.
I think your question was concerning total nutrients, not just N, so you need to do soil tests to determine P-K levels. Then, you can take into account other factors and apply accordingly.
Treat every lawn as an individual.
'98 chevy 2500 4x4 w/ meyer poly plow
44" Toro proline w/velkie 15hp kohler
various mowers (18-21-22")
Stihl stick edger, wb power edger
Toro backpack blowers
8HP Little Wonder
200 gal. elec. spray unit-lesco spreader