This will vary from species to species. In general most babies (less than a year old) should be fed an appropriately sized prey item every seven days. And then from there move it back to every 10 days or so, then back to every 2 weeks. Most adults are best fed every 2 weeks or so. You should watch the individual animal, if he is getting a bit on the obese side, for that particular species, cut back a bit. Many species of snakes can be "power fed", meaning trying to grow them quickly, without much negative consequence, but I don't think it is a good idea, they never seem as healthy as adults, and tend to be more prone to health problems. It also seems to be beneficial to allow a snake to have a full digestive cycle before feeding again. This also allows to see how long it takes to digest, and make sure they defecate properly. It's not a hard and fast rule, but it is a good idea with most species.
All of this is a general idea, you have to take the particular species of snake into account. Green tree pythons are generally fed a little less often, as their metabolism seem to move a little slower, and they are a bit more prone to digestive problems. Carpet pythons have high metabolisms and you almost can't overfeed them. Emerald tree boas have a very unusual digestive process, as compared to most captive snakes, and only defecate on average every 3-4 weeks, even if fed every 7-10 days, and are prone to a number of digestive problems, one being coined "emerald regurgitation syndrome", ERS, or "emerald vomiting syndrome", EVS. And this is not clearly understood yet on a scientific level.
Add to this that it's not always as simple as "feed the snake", sometimes a particular animal won't eat for various reasons, some won't eat when going into a shed cycle, or at certain times of year, (brumation, breeding times, etc...) or because of stress, etc...
I have numerous animals, and numerous species, and I keep a detailed feeding record, and for some, a detailed defecation record. It is the only way to keep track.
Most reptiles, and most snakes in particular, are opportunistic feeders. They eat when there is food. A healthy snake is almost all muscle. And "hungry" could be a relative term with a snake. Most snakes will become more active when they are hungry. Many species in the morelia genus, and others, will perch themselves with their head pointed down and start caudal luring, wiggling the tip of their tail below their head so it appears as a worm to lure food in striking distance. It varies species to species and animal to animal.
And allot of snakes will eat themselves fat. They eat when there is food available, and if healthy can go for long periods when there is not. So if someone offers a healthy ball python an over sized rat every week, they will eat weather they need it or not.
I try to feed my ball python once a week, but sometimes she refuses to eat for months on end, with no changes in health. Once a week is probably a good general interval for most common pet snakes. I hope you don't have a reticulated python or something while you're a novice (but if you did, try feeding it a goat once or twice a year).
Actually most I know who keep giant constrictors (reticulated pythons, rock pythons, burmese pythons, green anacondas, and to a lesser extent, amethystine/scrub pythons), feed their adults every 2-3 weeks, a prey item sized the same as for most snakes, about as thick or a little thicker than the snake is at it's thickest point. Of course at that point your talking about large rabbits, adult chickens, small &/or pot belly pigs. Just about any species of snake will be healthier when fed smaller prey items more frequently. An adult retic could definitely eat a much larger meal, but there is more risk of injury, and a much longer digestion time.
I have three glass snakes! I just got them about a week ago and I am wondering how often to feed them and how to know that they are hibernating and not dying? They will become active if it gets warm outside and becomes more warm inside but the last few days it has been cold and they have not come out that I have seen! I put about twelve crickets in the cage when they were all out the other day but I don't think they are any of them. How often should I clean the bedding if they are just staying in the bottom sleeping? And how often should I just get the crickets out of they haven't eat them? Any other information on them would also be greatly appreciated!