I'd suggest if you have messy code, make it a priority to tidy, even if you're not going to show it to anyone else. Just cleaning up the indentation will sometimes show you where a bug (or potential one) lies. Moreover, why make life more difficult for yourself - coding has pitfalls enough - no need to add to your problems by making it hard to read.
Lastly, I'm sure this varies by person, but the last thing I'm going to do once my code is working is to spend time prettifying it so it had better be neat already so that when I come back to it months later, I have some chance to understand it.