These recommendations are for carpet pythons, although you can adapt them to any number of snake species.
CAGE SIZE! The all important question! I’ll go into different materials and specific uses for each in the different heating sections, but this is specifically for cage size only.
Hatchling, now for hatchlings, if you purchased your hatchling, get it home and set it up just like the breeder had it set up and get it established at your house, then you can mess with it’s set up! Most of the time this is going to be a 6qt tub type situation. Not very pleasing to the eye, but works. After it’s established you can move it up to a cage size that should last it 12-18 months depending on feeding. This is where those exoterra cages will work, or a 2×2 cube by what ever cage manufacturer you choose. Things to make sure of is plenty of hides, and good temp control, as long as those are met they should be fine. There is a good thing about carpets and that’s that they once you reestablish them at your house they don’t stop. They typically aren’t shy about eating, won’t go off food unless there’s a reason etc. so hatchling to subadult you’ve got 6qt, to 32qt, to 41, they stay in 41 till they can go into adult cages. If it’s your only snake the progression can go slightly different, 6qt, to 2×2 cube, then to adult caging. The minimum adult cage size is 36x24x12, WxDxH, if you can go bigger, go bigger but that’s the smallest I’d go, if you keep adults in racks look for a foot print of 860 square inches as a good starting point. Materials, melamine is cheap, Pvc isn’t, and at least where I live it’s hard to come by also, so melamine it is for me!! Also on the 3.2.1 cage size you’ll want to exercise portion control on your carpets and try and keep them under 6ft. You prolly shouldn’t keep a 7-8ft coastal in a cage that size. The size caging I use is 48x24x12-15 depending on the animal, if you have an animal that you know doesn’t really climb why give it perching? I can use that space for more caging!! So that’s my thoughts on that, now if you have a snake like this 
Then by all means give them the option! The idea is to learn your animals and watch them and be able to tell what they want. They do talk to you, they just use different language and you have to be able to understand what they are saying. Try really hard to become a “student of the serpent!” As Eugene Bessette says! This is going to be a recurring theme in any care article I write. So just be warned.
There is a thought going around Facebook, that I refer to as the 4ft by 2ft by 2ft cult. Because they are very much like a cult, disagree with them and they will blast you, calling you all the names they can think of. The basis behind this religion is that the only size cage capable of housing an adult carpet is a 4ft by 2ft by 2ft cage, anything other then that is animal cruelty! There’s no real nice way to put this other just to say it, that’s pure bull shit! If you don’t see a point in giving a 5 ft animal a 4ft cage and want to give it 3ft then so be it. If you want to keep them in racks then do it. Most animals in captivity are way to fat and big. So keeping them smaller may be better! Ok enough of that soap box. Oh and if you stick around long enough you’ll eventually notice little clicks, like the heat panel click, the maternal incubation click, the proportional thermostat click. With carpets they are so variable, and so adaptable they will prolly adapt to any type of keeping you’d like to try. These guys really are easy!!
