I kind of feel that way myself. I've been reading bits and pieces of resin degrading. The tricombes turn amber. I've seen where some people think you should actualy go until you have about 10% amber but that seems too long. So, how long IS too long?
It's quite hard to go "too long" without your buds turning to mush. I NEVER harvest with less than 30-40% amber trichomes and I've never had a problem with couch-lock weed (I recently had some that went to about 60-70% amber on me almost overnight. I was a bit worried, but it turned out to be some of the best smoke I've ever had!). If you want a strictly head buzz just grow a Sativa
to maturity. If you want a really good stone grow an Indica
to maturity. Most of us like something somewhere inbetween, which is where the wonderful world of crosses/hybrids comes in.
Regardless, grow plants until they are fully mature if you want the maximum effect that particular phenotype is capable of. Most people harvest WWWWAAAAAAAAYYYYYYYY too early in my opinion, and only 10% amber is definitely premature. Most plants will really pack the weight on the buds the last 2 weeks before reaching their optimum. You usually have a 1 or 2 week window in which to harvest at that point, after which things will degrade rapidly and the plant will die (at least in nature).
How long is too long? I don't think there is any such thing as long as the plant remains healthy, and you are able to maintain patience --- which is usually the hardest part for me personally. Sometimes ya just can't resist nice crystal-covered buddage, whether it's fully done or not!!!