According to ifixit
Repairability score of the last three generations of iPhone is 7, and the ones before that (except the first gen) were a 6. Only one phone made in the last five years scored higher than an 8 - and Samsung, who was responsible for most of those 8s four to six years ago, went down to 3s and 4s with their last three year's worth of phones!
Other than the special screwdrivers, which are generally included when you buy e.g. replacement batteries or screens, iPhones are simple to fix. Their recent tablets and laptops on the other hand, are down at the bottom of the repairability list. I've never tried to take apart an iPad, but you'd think it would be a 'big iPhone' and assembled/disassembled in a similar manner. Guess not!
I bought a new laptop last fall (HP 17t) and swapped out the hard drive it came with with an SSD. Had to take the whole thing apart, and it was hard enough I had to go to the web for instructions and it still took a half hour! The days of having access covers on the bottom held by a couple of eyeglass screws for the hard drive and RAM are past, I guess.