id consider that some employers would prefer to see a stable work history. Not that i have one, but there was a period where i cycled jobs for a few years until i could find one that i could tolerate. Those i leave off. NO ONE is going to remember who did what 10-15 years ago, so i fudge the dates to cover the gaps.
it works for me, but im "job search lazy" and dont actively look for new opportunity. i guess things are still "tolerable" at the current shop.