Real golf balls lose compression as they are hit and as they age. Using old, out of round, lost to much of their compression golf balls is one reason many real life amateur golfers have difficulty scoring.
Back when I played serious real golf I retired each ball after using it for just 6 holes. In other words I used a sleeve of balls to play 18 holes. Those balls then became practice balls and replaced an equal number of older practice balls.
Consequently, I'm pretty happy that I can play pretty close to 54 holes with one WGT ball -Nike L85+ Vapor - that has a durability rating of 2.5 which = 120 hits of durability. Putts don't count as hits and don't reduce the durability of a ball, unless you use the Mulligan option available when playing Practice mode.
So with my scoring average of 62 and that I average about 25 putts per 18 holes I only use up about 40 hits of durability per 18 holes.