I bet Falco's the type who tends to over work his attachments. He's constantly pushing them to the limit so the tend to rub raw, get loose, or open, cutting his skin.

And someone, usually Fox will usually notice the Blood in the suit and march him into medbay, so he can dress the wounds, refit the attachments, and clean his prosthetics.

Of course, Falco being Falco will make a big stink about it

Fox, Falco © Nintendo