Textbooks provide us with the basic knowledge and what needs to be accomplished. As our industry progresses we gain more knowledge and insight. Manufacturers provide new and better equipment and methods. When I was in school they taught us how to troubleshoot to determine a dirty condenser coil. The class never mentioned me having to lug 150' of hose or the hundreds of coil cleaning products that are out there. My point is tool manufacturers provide us with training on use of their products and constantly upgrade. All products that are new aren't always useful but some are tried and true methods and make a lot of sense. As we personally progress we upgrade our skills and find new and better ways of doing things. For example, I have for the past ten years or so been using my reclaimer to empty new or recovered refrigerant back into systems. This wasn't in the course but it allows me to dispose of empty bottle on the job rather than carrying them around until I can reclaim them for disposal and also allows me to have reclaim cylinders available. Then sights like this one exposes us to many peoples methods and find out new and better ways of doing things. Also some of these items I believe should be provided by the company so they maintain a standard of quality control. It's hard to maintain quality control if one person uses a 4 valve manifold and no shreader pullers and another does. I have also been in situations where a guy doesn't own a micron gage so his evac is based on time where as my evac may require my pump to run overnight after a system repair to achieve 500 microns or better. My job took longer but it is what is expected of us as professionals.
They also sell all repair parts for that manifold set so as long as the ports aren't worn all o rings and seals are replaceble. Don't have any idea how much they cost. Only repaired a manifold set once in 32 yrs.
Just so you know most good hvac companies you go work for will provide a vacuum pump and recovery machine. some even provide a oxy-acetylene rig so I wouldn't go as far as spending all that money until you know for sure. Ask around and see if they provide one. Start doing work and slow buy those if you plan on getting your contractor license.
yellow jackets aren't a bad starter set, for the same price i like the JB's better. Once you start working in the field and making some money get yourself a nice set of digital gauges like fieldpiece or Testo.