When is your Hifi good enough?

It depends entirely on the individual. Some people are always on the "hunt," while others find a comfortable patch of audio goodness and stake their claim there for the long haul. I used to belong to the former camp, but for the last five years or so, I've been firmly in the latter. I know my system can be improved, and I may make a few small tweaks here and there to get me a little closer, but for the most part, the rig does the trick for me, and I haven't felt the need to make a big change in a long time. I think I got the fundamentals right, and that's a big step. If something blows up and I need to replace it, then that's a different matter! :)

The best measure for me I can come up with for if my hifi is good enough or not is how much time I spend listening and how much I look forward to the opportunities.

If my interest wains its usually an indicator that something is not right because I have always looked forward to spending leisure time just listening to music.

Just got through 1812 Overture on Mercury Living Presence  cranked to fairly realistic volume.  I am just getting of my knees where I was crying and sobbing.  😩

Its good enough.     Blew me away and nothing blew out in the process.   😗

For 30 years my receiver based system was good enough.
....then I discovered Audiogon and the word 'audiophile'.
I've been pursuing the elusive holy grail ever since.

"Mamas don't let your babies grow up to be audiophiles"

"Mamas don't let your babies grow up to be audiophiles"
or
"Women don't let your husbands become audiophiles"

2015 was a year of upgrade after upgrade for me, after we decided to have me migrate the audio system from the living room, to my "man cave", a much larger room.
After installing my sixth bass trap (to control the boominess in the room), my wife said "I've unleashed a monster".
But I'd say I'm about 95% of the way there now.  Oops, just ordered a new headphone amp...