This is the second most contended subject on the board, 308 v 30-06 being first. It's personal preference, I develop loads for custom rifles
that are smith fresh to my door. I break in per the barrel manufacturers specs on those, but on my personal custom rigs I prefer the following method. Clean barrel spotless after each round up to 50. No brushes Period. This makes cleaning in the field quick as 3 patches. Some people consider this meticulous and anal, but it has made some seriously accurate rifles. They get gobbled up when I sell them.
On my factory rigs I do the multiples break-in, clean after 1,2,4,8,16,32,64 DONE. Different types of cutters and equip. are used to make different barrels, so the manufacturer has the best idea of how to treat their barrels properly.
*Trick* Clean the barrel completely to the best of your ability- Now run a patch with breakfree down it... I thought you cleaned that thing! It's always black when I do it too!
1. No brushes!
2. Breech to muzzle
3. Plastic coated rods only(a throat is a terrible thing to waste)
4. Use a rod guide
5. Never store the barrel naked
Do as you please, this is just a recommendation.