My friends sent me some photos showing his 3 years old BH with close to 1000 nests. He has 2 BH. The first BH was built by a consultant, but after close to a year, the result was very poor. He then decided to terminate the contract early and started modifying the BH himself. Now he is building another standalone BH.
He give a lot of tips and comments on my BH free of charge. I feel very fortunate to get to know him.