3D models you create are helpful because they solve your problems for you when you are completing the design. You need something that shows you every nook and cranny of the design, and you will start noticing parts of the design you never thought of before. You need to have something that will help you when you are trying to complete the design, but you also need something that susses out all the errors. You will make mistakes as you are drawing, and you cannot avoid them. You catch them when you have 3D models right in front of you that show you what is going on.
You want to have these models ready to go for other people so they can check them for errors. Your errors get much worse when you do not catch them the first time, and you go on with that error for a long time without any way of fixing it. That is a major issue that you need to solve before you get too deep into the program, and you need to start considering how you will make changes to the model.
You are working with people who will expect you to make changes once you find errors, but you will avoid most errors after checking in a software program. The best programs will help you find errors that make no sense, and you will find a few problems that make you change the whole idea. This is the only way to design because everyone who works in the 3D modeling business does the same thing. They expect to see the design change a few times before it is complete, and they expect you to check it for errors. You can do both of these things using one piece of software that you find online.