The film industry is a creative industry, although many of the departments have a lot of tech and tech oriented people. Having your own equipment will eventually become a great way to increase the amount you can make from each shoot.
When you’re first getting started as a production assistant, a smartphone with unlimited data will be essential and the extent of what tech you’ll need. GPS is going to be your best friend and often you’ll want to be able to look things up for the rest of the crew.
Eventually you’ll start to move into one of the departments, and, broadly, most people will want to get a laptop. For camera, editors, and sound, this is a place to store and access files from and during the shoot. It might also be a necessary purchase so you can work on editing your reel. For the people working under the producer, a reliable laptop will be invaluable and not having one could reflect poorly on you and hurt your reputation.
As you go farther into your craft, specialized equipment will become a way to make more money and stand out as a more “all-in-one” hire; it’s easier on production if they can make a single call to get a Mixer or DP, for example, who also comes with the necessary equipment (and won’t overcharge them). Although equipment like this can be very expensive, it can pay for itself quickly when owned by an in-demand professional which is why we focus on the things we do here at FIF.
The art department is in some ways an exception to the rule. You probably won’t need anything beyond a phone until you become a Production Designer, the head of the department, when you’ll need to show photos and mockups to the director.
All this is good to keep in the back of your mind, but the important thing is to get on set and start working. Ask other PAs what they have bought and bring to set, and once you start angling towards a craft job, ask the people working it what they’ve bought, what brands they like and don’t like, etc. Like we say, ALL answers are found on set.