There were some things we ran into in the walls that have been somewhat of an eye opener for me. The outside is sided in sheet metal, and over the years there have been holes cut and damage from trees. Every time there was a utility installed, there was a new hole cut in order to run cables into the house. Here's a great example of a slash in the siding (probably from a tree) and a phone cable coming into the house. Not sealed at all!
And then there was this little guy. I have no idea what he was or how he got in, but I can't even believe he was there! Holy Cow! Luckily the insulation that was there helped mask the smell. This house is about 16 years old and I can't believe how much deterioration has happened in this time. Hopefully with the repairs we're doing and the quality materials we're putting in, it'll give us another 20 good years before we have to do any major renovation on this mobile home.