I just did a quick test on my preferred soil mix for potted cacti, agaves, aloes, and etc.
I filled a one gallon pot with my mix (~33% pumice added to a balance ~67% of 'premium' cactus and succulent soil that already has some fraction of pumice [I'd say maybe 10% max]) to maybe 1/2 to 1 inch below the rim of the pot. The pot is a pretty standard black nursery pot with five holes, four on the bottom side and one in the middle of the bottom. I started watering it with a steady but not hard stream of water from a 5/8" hose in the center of the soil, I have a 90 degree ball valve on that hose after the tap that was maybe 25% open. I started seeing water come out of the first hole in about 8 seconds, by 15 seconds there was water streaming out of all holes, the flow of water was never large enough and the soil drainage was good enough to never have water pool on top of the soil. Obviously, if you have larger pots with different numbers of holes the result of this kind of a test will likely change, but it should at least give a sense of how fast water should drain through an effective cactus and succulent soil mix.
I'd say though, that unless you have a giant pot, if it takes more than 1 minute for water to start coming out of the bottom of your reasonably sized pot with a good number of drain holes, then your mix is not fast draining enough.
I have a number of legacy pots - largish pots filled quite a while ago with previous soil mixes when I still used sand and other additives beyond my current mix, or occasionally when I was out of pumice to add and I can say that when I water those they take longer to drain and some will have water pool on top of the soil in the pot for quite a while. I live where generally it is warm enough (and I am likely lucky that plants in these pots are pretty forgiving) for those kind of poor drainage conditions to not be a giant issue - but I definitely take care to not water these pots as frequently as they also do not dry out as fast as my current 'preferred' mix.
I also have some pots that over the last few years have become mostly pumice and roots, those drain super fast and they dry out so fast that I can almost water these pots every day since water retention when it is warm is minimal. Most of these are in my 'need to be repotted or put in the ground' queue.
