only where gloves for spray painting as paints a bitch to get off and i don't want to get any grease from my hands on the cleaned parts.
as for mechanical; never wear gloves, never have worn gloves, never will wear gloves, ... because i don't have a mangina
at most if i was struggling with my hands and certain chemicals i'd possibly use a barrier cream but thats about it. i like to have full feeling through my finger tips etc, especially when you're doing some things blind etc.