Would you put together a model plane without look at the finished plane or looking at the plans? Does a builder build a house without a plan?
The answer to these is pretty clearly no. A homemade snake or other reptile cage is so much simpler though, you say. I can just put it together as I go. Not so, my young apprentice. There are many pitfalls awaiting the inexperienced. Simple things you can miss. Silly mistakes you can make, and believe me, it is very easy to make them. There are a host of things that can make a simple cage take much longer than it should plus some possible costly mistakes.
If you have never kept a reptile, then before you even plan a reptile cage, you need to do some research on what sort of cage your retile will need. A snake will need cages of certain dimensions; lizards will need other dimensions and arboreal species yet another type of cage with different dimensions. It's also helpful if you know how large your pet will get so you can plan ahead.
Another benefit of a plan is it helps you to think about your pet reptiles other needs such as heat mats, basking lights, UV lights, misting systems, substrates, decorations such as artificial walls, artificial trees and branches, and how these can be made and placed in the cage.
Once you have a clear idea of what you want the finished product to look like and how large it will be you are ready to plan how you are going to construct it. At this stage, having a plan, however rudimentary, is important. Once you have a plan in place you can think through the issues. In many cases it will allow you to remove the problem before you even start, as the plan often reveals an error or issue. Naturally, the more detailed the reptile cage plan, the more you can make allowance for possible issues. It can also eliminate waste and save money as you only purchase the correct amount of material.
Having a plan is useful as it allows you to see and understand how the cage will be constructed. You can work out how you may want to alter the plan if you feel the need to change.
And finally a plan is essential for the construction phase. What goes where, what is the order of construction, what size should this piece be and so on.
When building a reptile enclosure if the plans are detailed enough you will find that you constantly refer to them. This also helps minimise costly errors.
Using a plan, whether is be yours, a purchased plan or someone else's, will save you time, money and effort and produce a much better results for you and your pet reptile.