Do you guys every look back at some of the older stuff you've written and get the feeling of not really wanting to change it? I'm almost finished with my second novel and I've been occasionally looking back on the first one to see what can be improved. However, the only thing I'm really changing is some spelling, punctution, and grammar mistakes. I can see where my writing style has improved and how I could add to the first novel, but I still don't feel like I want to mess with it too much.
Yes, I actually do. Perhaps the grammar isn't the best, but the ideas were. If you don't feel the need to change your old novel - don't. In my opinion, you're ruining it. It was a lot to complete and as you said, after writing it, your style improved. If you do feel like you must change it, do as my friend Mallory does: open a new doc and change what you like, keeping your first draft unharmed
Unless you plan on trying to publish your first book, I'd say don't mess with it. You wrote it, you learned from it, now it's done. Your time is better spent writing a new novel (which will undoubtedly be better than that first one), not messing with the first one.
I did feel that way, but then found the British Writers Award. After reading my first book I decided I could do it better and I am in the process of rewriting it. Personally I am so glad I have its the same story. However the characters and their interactions are so much better, the descriptions are better, the legends work better and it is a much better book. I was worried I might ruin it but I haven't.