I find it handy to have a small mirror in the workshop. Two primary purposes:
A: Looking behind or under things - a classic use of this type it threading the 0.25 mm wire on my Wire EDM machine that has to be threaded upwards from under the guide arm. But it's also useful for looking at dial gauges 'round the other side of items' etc
B: Personal care - I have a false eye and on occasions - if for instance I rub it, it can swivel looking in odd directions and potentially scare the horses if not attended to before I open the door to callers !
For years I've had a pack of 6" square glass 'mirror tiles' that over time have gradually been broken - these are an ideal size but for some odd reason seem to have gone off the market. No problem buying acrylic ones (mostly self adhesive backed) but plain ordinary glass seem to be unobtainium.
A few days ago I was watching a video of a chap converting a totally enclosed unsinkable life boat into an arctic expedition vessel and not wanting glass on board he had got a sheet of mirror polished stainless steel. What a good idea I thought and went hunting and found this chap on eBay. Two 6" squares delivered today and they work splendidly, and THESE won't get broken!
https://www.ebay.co.uk/itm/Sheet-Metal-Stainless-Steel-Brass-Mild-Aluminium-Galvanised-Mirror-Polish/164709944874?ssPageName=STRK%3AMEBIDX%3AIT&var=464211943857&_trksid=p2060353.m2749.l2649