Started flying 1969, only have military computer logs til 1977, which only log time, approaches and landings (not TO/Landing fields). After that (when told by FAA to keep logbooks for ATP license), I started a formal logbook.
I would give left nut (almost) to be able to read when & where, with comments of unusual happenings, of flights '69-'77; alas, they are gone (except for vague images). '77 on, have info; usually with copious amounts of wine, it amuses me to read back on experiences & screwups I have made & survived. Young guys, keep a logbook; if you're not sure whether to make a comment, make it! 25 years down the line, you will savor same. Sam