I used to be of the "never clean until accy drops" camp. Two things happened that changed that.
1. I had a 6.5x47 go out on me at 900rds. I had cleaned once or twice during that time. I ended up needing to troubleshoot 4 or 5 things to try to figure out what the deal was. Clean the barrel, measure the lands and chase, mini-load Dev to try to bring it back in tune, etc. That eats up 100 or so rds and a couple of days if you can shoot every day. And the chore of cleaning a very dirty barrel is worse when you don't keep up with it. Coppering and carbon rings are the two big ones that catch guys that don't like to clean and build up over time. And they're a bitch to deal with after the fact. I also now believe that throats erode slower when kept clean, but I don't have any science to back that up. Just my running theory until I find out different.
2. I shot an Fclass match with my gunsmith. He cleans his rifle after every match. Goes into sighters with a clean bore. Shoots 42 out of 60 rounds across 3 relays into an aggregate 1/2 moa F open Xring at 600yds. The throat on his XC eroded fractionally less than my x47.
I now clean my match barrels after every match. I measure the lands on a clean throat, borescope it to observe the condition of firecracking, take notes on that barrel's portion of my dry erase board and then hang the barrel up. I like to know the condition of the barrel. I don't want to "set it and forget it" and then have to go thru the 7 steps of grieving/ troubleshooting when I lose velocity or accuracy.
Additionally, I have have 11 or 12 TL-3 barrels hanging on the wall. In various stages of rd count. I need a system that eliminates the headache of keeping up with that many projects, loads, and degrading barrels. I can't just mil'it & kill'it with that many barrels without getting lost in the sauce. Now, i don't clean excessively. Boretech Eliminator and patches. Every couple of cleanings a brush will come out depending on how the coppering looks in the barrel.
Here's a question for you: When are you going to find out that you lost accuracy?
Answer: In a match.
If you never clean it, statistically you have the greatest chance of being presented with a problem during the 80 - 250rd match. Not during your 10rd zero check & true.
I would also caveat that the rule of when to clean can't be generically applied to every type of gun. ARs, suppressed, unsuppressed, pistols, bolt guns have different needs.