Once yes. Most of the prior people were still with the company. They had design document, file comments, function comments, and a few (very few) inline commen

Once yes. Most of the prior people were still with the company. They had design document, file comments, function comments, and a few (very few) inline comments. All code development was done under contract, where the documentation and code reviews were deliverables. Twice no. One was a massive in-house project that had evolved over the years. There was a former developer, but he was not very good, and only wanted to add more bells and whistles. He got frustrated with my efforts to document the code and left. It was used to help test other code, but was the most horrid thing. Second was 5 years ago, person left, and left literally no documentation. We had a weeks overlap, and he demonstrated the code, but in the thousands of lines of code there were a handful of comments that just had the date and his initials. For me I need to be able to understand what the intent was of the code. Then I can either debug the indent (i.e. bad logical thinking), or implementation (not coded to do what you want).