I bought one of these kits three years or back to repair my Google Nexus 6P phone and have used it for all other repairs and inspections of gadgets. It has all the screwdriver bits you need for weird screws you find, tweezers, and item to pry cases open. A nice touch is the bo lid that will hold all the loose bits you remove from devices.
The only extra items I've needed were a good heat gun, a vice to hold things, and a strong magnifying glass. But to undertake any repair (even vehicles) you always need the right tools and something like this is essential for gadgets and phones.
Apple has recently made it easier to get your iPhone fixed from third party shops. But if you want to repair it—or any of your other gadgets—yourself, you’ll need the proper tools. Fortunately, just about everything you could ever need to fix just about any electronics can be found in this iFixit Pro Tech Toolkit.