The only new piece of hi-fi kit I have bought in the last ten years is the M-DAC+, and then, only because my PT Ordinal finally gave up the ghost by killing the PCB tracks where some of the power caps were. My modified Meridian 602 transport is still working and the MF P170 has gone through a number of incarnations with modifications/repairs since I purchased it new from Doug Brady Hi-Fi back in 1990-something, and I hope Arkless would approve.
In the past though, I have repaired a Nikon 50mm f1.8 manual lens, on a kitchen table whilst holidaying in Scotland, back in the 1980's but I certainly wouldn't consider doing that with modern lenses, especially when Nikon serviced my 24-70 f2.8 AF-S lens and charged about £110. This included replacing the mounting and some of the exterior body parts. It looked like new when it returned.
When I replaced the main temperature sensor in my now 14 year old Zanussi by Electrolux oven, it took almost three hours to do, as virtually the whole carcass, and ceramic hob top-plate had to be removed. Not so much a trial, but certainly uphill. Suffice to say, the main element has now failed, but I'm loathe to go down the route of replacing it, as the plan is to install a new kitchen anyway at some point. At least with most white goods, there are spares available, and if you are competent, you can elicit a repair at minimal cost.
Like others, I'm not one for having to purchase the latest all singing, all dancing latest fad product, I make considered purchases that I know will last a long time and give value for money. Going back to photographic equipment, I only "replaced" my Nikon D3 in 2018 with a D850, with the D3 giving 12 years of service, but still being used in addition to the new kid on the block. It's the same with the Gitzo tripod. Although there are newer models, I don't feel the need to buy one, as there is nothing wrong with the Gitzo, and it's the same with the LowePro camera bag. All 12 years old and still in good working order. What I would have liked with digital SLR cameras, is the option to upgrade sensors. It is possible with medium format, albeit for different reasons, but going back to 35mm film SLR's, for example, it was the film itself which was the upgrade as manufacturers like Kodak, Fuji and Ilford, improved emulsions, dyes, grain structure etc.
Another hobby of mine is 0 Gauge railway modelling, and you should see some of the issues people have had with brand new ready to run items produced by Heljan. Gear-trains were splitting and cracking, and although replacement parts were available for a time from the UK distributor, Heljan eventually washed there hands of the problem. I believe it took almost two years for Heljan to admit there was a problem and changed the manufacturing process for their gear trains, but it left a sour taste for many. People who are now experiencing the same problem are having to source gears from a third party at extra cost. Although repairable, for some modellers, it is the additional cost of now having to repair a model less than 5 years old with after-market parts.
Ian