Our boat's factory Hobbs meter was working when we became the second owner in 1994. Approx 1000 hrs, and it had been used quite a bit for a big sailing club on SF Bay.
When I replaced the original engine last year it showed about 2300 hours.
New engine now has around 30 hrs. (Too much going on around home to take the boat North this season, so it simply got used less.)
Interesting that quite a few owners do not have a working hour meter; that's my measurement tool for oil changes, etc. along with the calendar.
Actually, now we have two such displays -- the new Betamarine panel has a digital hour readout incorporated into the tach display, and since I wanted an easy-to-read one, I installed a new meter in the engine compartment. Thanks to the internet, a good quality one is not very expensive, in any case.
I did have to cover the original round meter face hole in the side of the engine compartment, tho. Pix in my blog.
Probably it's just me, but when shopping a used boat (or even a vehicle), even if the seller seems very trustworthy, I am a bit skeptical of a disabled or broken hour (or elapsed mileage) readout.
I know how expensive a new/rebuilt engine can be, and want some assurance that the maintenance in the past was performed with due diligence. I do suffer from an excess of caution sometimes.