You can absolutely hire a tile setter, a plumber, an electrician and a cabinet installer yourself. Plenty of people do. What you are taking on when you do it is the part that is invisible until it goes wrong: sequencing, liability and accountability.
Sequencing is most of the job
Trades have to happen in an order, and each one has a lead time. The plumber has to rough in before the drywall, the drywall has to be done before the tile setter, the countertop cannot be templated until the cabinets are set and level. Miss one handoff and you lose a week, then the tile setter is on another job and you lose three.
Licensing, permits and insurance
A licensed general contractor pulls the permits, books the inspections and carries the insurance for the work. If something goes wrong on your property, that matters enormously. Ask any contractor for their ROC number before you let them start; ours is 309760, and we are bonded, insured and BBB accredited.
One person is responsible
When the tile meets the flooring badly, is that the tile setter or the flooring installer? Managing it yourself, that argument is yours to referee. With a GC it is one phone call, and the answer is that we fix it.
What you should still expect
A written itemised scope. Real dates. Changes priced in writing before the work happens. A warranty when it is done. If a contractor will not give you those four things, the letters after their name are not worth much.
