Good question. I found that generally there is a small tolerance that happens in the beginning. So, for example, when I started, I took 2.5 to 5mg, but after about a year it went to 8.5-10mg and and has then has stayed there for years. I can say that I've had a few bad nights over the years where 10mg wasn't strong enough due to extreme stress (like a death of a family member), so I upped to between 12.5-15mg for that night, and then went back down to 8-10mg after two days and stayed down again. Talking with various shop owners, some say they often see a very slow growth over the years, and people will get to higher amounts, getting to 20mg or a little more. But, now I'm talking 20 years of slow growth. However, I do know that you can also reset yourself by not taking it for a few months, and start over again (maybe not 2.5, but it depends on the person, 5-10mg is pretty normal for most people aiming to sleep). If you do this route, my suggestion is to also use a smart watch to track your sleep to help guide you on the right strains and timing, you can't always tell subjectively if what you took is the right amount, or needlessly extra. This helped me find which strain worked best. For example, there's a brand called TasteBudz, that for me, does work but I only get about 1 hour of deep sleep per night, and I can see I am restless for several hours. But I felt ok, so subjectively I might not find anything wrong with it. But then I tried a brand called Wana, specifically their blueberry Indica, and that gives me a solid 8 hours and 2 hours deep very consistently, no matter what I eat, and I wake up even more refreshed. I have an entire notebook full of which strains work, which sorta work, which don't, and both the objective scores such as sleep patterns, along with my subjective notes. I've even tried blending different things to see how they did, with so far mixed results, although cannabutter products like the cookies do seem to blend well with other things the most easily. But that's just me horsing around, I have my "go to" brands for sleep established, I just like to tinker. If you can, and this works, apply for a medical certificate so that you can get it even less expensively (often close to half the price). However, even if you can't get one, it's still a very inexpensive way to get some sleep. You spend about a dollar per 5mg, so 2 bucks a night is a great price to sleep.