Yesterday, but replaced the 45A double-pole isolator switch on my friend's shower. The pingfuckit responsible for the latching operation of the pull-cord wossname had broken, which is bad news after a hot >100k ride to get there.
Being somewhat covered in road grime, squished insects and so on, my natural response was to sigh and ask for a screwdriver. Various options were presented, including sonic - though that was sadly unable to rectify the fault - so I soon had the switch off with a conventional one and important springy bits flying across the room. I deemed the cause of failure to be snappy plastic death.
All things being equal (and bearing Kim's First Law Of Adhesives in mind), jumping back on the bike to the nearest DIY emporium for a new switch seemed like the sanest option at that point. The guy on the till was amused by a sweaty cyclist buying what was obviously the component that stood between them and a shower.
Bit of screwdriver-twiddling and job's a good'un. Part P allows for like-for-like replacement. Especially when you're starting to smell like a dead badger.