I've worked on a number of inherited projects of varying quality. The biggest trick is to figure out what is working and what is broken, what's minor vs major.

I've worked on a number of inherited projects of varying quality. The biggest trick is to figure out what is working and what is broken, what's minor vs major. In that regard, you should try and get someone who uses or used to use the application to walk you through it. Then like taproot focus on the important parts or the small-hanging fruit. Also if the project is small enough, it's often very informative to manually trace out the main code flows. Also if you're having trouble understanding the programmer's style it's often useful to understand their background. Often the style or technique they use is because they have a background in a different language/library that uses it. EDITED: Personally I would avoid changing the style, because it's quite easy to make a typo or mistake that's hard to catch because you don't understand the application.