Starting on a budget..
If you pursue residential and or commercial you'll need an extractor either way. Get a simple one with lots of suck. 500 psi and at least two 3 stage vacs. External heat source is best.
EDIC, Masterblend or Ninja all offer nice compact units. Many portable are so damn big you'll need a helper just to lift and load.Keep your hose runs short and use a wand with 6 flow (ask the salesman to set you up)
a 175 rpm floor scrubber is a must. It will pre-scrub, post bonnet and allow you to shampoo/encap areas as well. Get a 17" version and if you can find a two speed 175/300 in your budget it will speed things up. You'll need a pad driver for fiber pads and cotton bonnets and you'll want a shampoo brush as well for digging deep on pile carpet.
A basic PMF internal upholstery/stair/detail tool with a hideAhose set up is a must too. Get a
glide for you wand and or a hard surface wand and you can scrub and rinse tile, VCT, Concrete and other hard surfaces as well. Always look for additional work once you've gotten in the door but don't be stupid about it and start cleaning surfaces you know nothing about.
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