Like most engineers of my generation, I still interchange between metric and imperial depending on my particular situation. For most practical matters, it's of little importance and a concrete base for a large garden shed will be sufficiently accurate for its purpose regardless of the methodology employed.
When it comes to fine and/or accurate work, theodolites, dumpy levels, lasers, internal and external micrometers do the job and feeler gauges and vernier calipers are also useful instruments. Fortunately, by and large, most of us will never have need of such tools to mend our bikes and our biggest challenge in mix-n-match issues is probably deciphering wheel rim and tyre/tube nomenclature so that we avoid picking up the wrong item in Halfraud's.
For a long time it seemed as if political correctness ordained that everything in our lives was destined to become metric and decimal but thanks to those wise people in Brussels, we really don't need to go that way at all and following the monumental judgement of the European Court a few years ago, our market traders are perfectly free once again to advertise and sell their wares in the same quantities as did their forebears. Recently, I was really pleased to walk through a street market with several greengrocers, all of whom had their fruit and veg marked up in pounds and stones.
Sadly, the chap from the north-east who campaigned to have that option but was prosecuted more than once by trading standards, failed to live long enough to see the re-introduction of the old terminology. He was vindicated, not by any court in the UK, but by the court central to the EU that so many in this country love to condemn for not having certain vested British interests at heart.
Overheard recently in Travis Perkins: Youthful yard boy - 'Ow much d'you want then?' Builder - "About 'alf 'undredweight oughta do it!' Yard boy - 'Ow much?'
Tom