the more you learn about time the more you realise the only logical way to keep it is tied to the positions of the planets relative to stars, this is the slowest changing and most precise way to define it.

and time is always relative to a place.

time in space goes faster than it does down here on earth, for example, and even faster in close proximity to big things like the sun, jupiter and saturn.

only really the shortest time periods have some relevance to short term events, like chemical reactions or growth rates.

insects and lizards and other cold blooded creatures, plants, crustaceans, bacteria, these all have their change rates strongly tied to the ambient temperature and gravity.

it's quite relevant to why synchrony in distributed systems is such a hard problem. even given identically manufactured, equally high quality time keeping devices, the density of matter around them, the altitude, all impact their relative differences in time, and synchronising between them is fraught with vulnerabilities where protocols use timestamps as criteria.