Given that Brooks saddles have a very long life tensioning it should be the exception rather than the rule. It's the 'odd 1/4 turn' that destroys a saddle unless you have a magic eye which can tell when the leather is shrinking and then turn it a 1/4 the other way.
A little sag is better than no sag IMHO. The leather should only be in tension when you are sitting on it. A little sag shows the saddle is 'relaxed' and not being stretched has a little room to shrink if the temp/humidity dictate.
I had a quick look under my saddle and there are ~20 available threads on the tension bolt. If I give it a '1/4 turn' every 2 months I can destroy it in 13 years. A 1/4 turn a year and it will only last for 80 years.
A little sag is better than no sag IMHO. The leather should only be in tension when you are sitting on it. A little sag shows the saddle is 'relaxed' and not being stretched has a little room to shrink if the temp/humidity dictate.
I had a quick look under my saddle and there are ~20 available threads on the tension bolt. If I give it a '1/4 turn' every 2 months I can destroy it in 13 years. A 1/4 turn a year and it will only last for 80 years.