My breaking point so far hasn't really been cost. We've been mostly going about once a year for the last 15 years or so (and I've been going since the early 70's as a kid, with some breaks for a year here and there due to lack of vacation time, etc.), and costs have risen dramatically over that time, even including discounts. We justified that by saying that we got a lot for the money. My breaking point is if the value we're getting for the money drops. That has actually been happening for a few trips now, with all the extra planning needed to get the most out of a WDW vacation. And that is for overall less to do for the money, with Disney closing favorite attractions in EPCOT and DHS with little or no announcements of replacements. Now with FP+ and literally planning individual rides at 60 days out or probably missing out on them, our upcoming October trip which I foolishly booked over a year ago, I'm seriously considering not returning afterwards. All that scheduling seems too much like work for my taste. We can luckily afford to still make a trip to WDW once per year, but other destinations are looking like better values for that money.
This is where I'm at. We moved farther away a couple of years ago -- while we lived farther South I could take my girls down for weekend trips to do
MVMCP and
MNSSHP (drive down Friday, go to the party, spend Saturday either at DTD or a water park and drive home that night or Sunday morning), and we did family trips every couple of years. This is our first full family trip in a while and, while I consider myself to be an uber-planner (spreadsheets make me happy.....), having to schedule FP+ 60 days ahead of time takes all of the spontaneity out of our trips. I had to change the plans for my parents just this week (they decided to add a day to their trip with us in August) and trying to make sure I could get them FP+ and ADRs since we're inside the 30 day window was stressful. We worked the old FP system and were able to do multiple rides on our favorite rides each day, and if we wanted to be spontaneous and park hop on the spur of the moment, we could. I feel like that kind of spontaneity is decreasing because wait times are increasing for so many things that didn't used to have long wait times. My husband doesn't like feeling so locked in and overscheduled and I honestly expect that he's going to want more resort time on our trip next month than in past trips. Prices are going up SO fast and really, it's insane how much Disney is charging for some things. For us the vacation is about being together with family and having fun, being able to relax and enjoy ourselves and ride our favorite rides until we can't see straight anymore...LOL....and so I'm really worried about how our trip will go next month. We aren't extravagant (use military discounts, military salute tickets, don't eat TS every day, share meals because we're not big eaters), and we're driving down instead of flying, but even so, our trip (four park days, one non-park day) is costing a lot more than our longer trips have cost in the past.
And then there's the value aspect. With so many things closed, no replacements, lengthy refurbishments, insane length of time just to build a parking garage, etc., I feel like the value isn't what it used to be. We've noticed a definite decline in customer service, park cleanliness, and overall maintenance since our first trip (either 2007 or 2009 -- can't remember now what year our first trip was!).
Our kids are getting older -- older DD will turn 21 this year and younger DD is 16, so the days of family vacations with just the four of us are probably coming to a close in the next few years.... My girls are asking to do a cruise next and my husband wants to do an all-inclusive somewhere on a beach, so I think we'll start looking at that for our next family vacation. My older DD and I are the big Disney fans -- my husband and daughter are more "along for the ride" and would prefer to try other types of vacations, and so I think that's what's going to happen for our next couple of vacations. I think I'll push for another WDW trip after the DHS renovations are done, so it will be a few years.
I still want to go down and do the Princess 5K with some girlfriends, so I may have some weekend trips of my own in the next few years, but I think this is our last family trip to Disney World for a while.