Oh so many things....
Fridge: Our refrigerator is 18 years old and at some point in the not-too-distant future will have to be replaced. I HATE stainless steel side-by-sides (the overwhelming option available where I live), and I hate the "French mount" style even more. I bought one of those to put in a house we were selling, used it for two months and decided never again. I took the old fridge with us to our new abode and it's humming along for now, but the ice maker died years ago.
Mattress: The mattress we adored when we bought it ten years ago is now starting to cave in the middle. It's a 10" slab of memory foam, but I guess foam degrades over time? Mattresses you can go lie down on and test cost too much, but how can I choose a mattress over the internet???
Ordered a Loom & Leaf mattress last week! *fingers crossed that it's AWESOME*
Update: 1/20/2018 - it is indeed AWESOME!!!
Washer. Man, they don't make stuff like they used to. My previous washer lasted 18 years and still had life in it when we sold it (it wouldn't fit in the new place). I had to stack, so I got front load. Eight years later, it is rotting from the inside despite our following all the instructions on how to keep that from happening. So far only the washer stinks - not the clothes or linens we wash in it. But it's going to have to go.
UPDATE 1/20/2018: Changing detergent to Norwex's enzyme-based Ultra Pure Plus has SOLVED my smelly washer problem, thereby postponing this purchase indefinitely.
Laptop: My current Dell Inspiron is 5 years old. It's hanging in there, for now, but eventually I'll need to replace it. I hate getting a new computer. UGH. All those changes! UGH UGH UGH.
Kindle & Kindle Fire: My Kindle Keyboard is from 2010. My plan is to replace it with a Paperwhite eventually. The Kindle Fire is so stupid cheap now it's hard to resist, but my first-generation version is still working, so.... I use it as a spare repository for ebooks checked out from the library and watch Netflix on it. What I really want is an iPad Mini, but can't begin to justify the expense.
UPDATE 1/20/2018: My husband gave me a Paperwhite for Christmas! I loooooooooove it. And he's now using my old Kindle Keyboard.
Eyeglasses: I am no longer delaying this expense. Our vision coverage is changing Nov 1, and it's way, way worse, so I used the vision coverage we currently have to get new everyday, computer, and Rx sunglasses. The everyday and sunglasses have progressive lenses, and I'm blind as a bat, so those babies aren't cheap. I haven't bought any glasses for five years, so my hope is that these will last me a good long time. I paid for them out of the HSA, or, as my husband calls it, "the fake money."