I will preface this by answering this question bluntly- I have enjoyed trying new gear. I like really short focal lengths, really long focal lengths, and everything in between. It is part of the hobby that brought me joy so far, albeit expensive over time so I am slowing down.
Also, I will note that having multiple refractors can also make sense, as they can be very different tools in a decent aperture spread, based on eyepieces and mounting solutions.
There is a propensity to want to collect refractors, just for being drawn to various functional equipment with some overlap in usage and liking all of them, and not wanting to sell them. No logic or critical analysis here, just pride of ownership and enjoying time under the stars with each refractor.
But let's dig deeper.
What does it mean to be content? This is particularly important for people without larger budgets and can only afford one refractor, and want an apo. Let's face it, they aren't cheap- if you told someone who isn't in the hobby pricing on various apos, even achros. You get a much better bang for your buck going the newtonian route.
Subjectivity comes into play. But for each person, I suspect it involves having a refractor that fits your observing habits with your equipment, which results in an optic that brings you joy and you use it lots.
Apo refractors typically excel in star aesthetics, wide field viewing, amazing for lunar and solar viewing, put up great planetary viewing for a select few planets (Jupiter, Saturn, Mars, Venus). Little fussing with the set up because of no collimation. Another large aspect of contentment involve having good build quality and mechanics, like the focuser or with some people, a sliding dew shield, ect.
But in the smaller sizes they fit on the smallest mounts, transport very easy on road trips even in small cars, cool down very fast. Very light weight so they can be used when there are lifting constraints.
This points to having them dominating in grab and go observing. This means more time under the stars, which brings all of us joy. After all, the best scope is the one you use.
Getting a refractor that checks all of these boxes will lead to the most contentment, especially those with limited budgets and can only chose one. Hence, the healthy preowned market.
I am young enough to get to enjoy this hobby for decades longer. I will likely start a collection of the simple sake of enjoying various designs.
But for now with a limited budget and time for observing at this stage in my life, I seem to be completely content with one of my refractors. I can't think of how it can be improved in any way. That means other scope choices should be based on complimenting it, unless I am going the illogical collector route.
In time, I will eventually be down that path anyways(but not right now).
Edited by Tyson M, 07 December 2019 - 12:55 PM.