It all depends.
I just installed a toytech 3" lift kit, the instillation time will vary according to your ability and how stubborn the parts are. I have a 2011 SR5 with a 100,000 miles so my hardware was tough to get off. I also did it myself and I consider myself a newb when it comes to auto repairs.
With the right tools and a healper, you could install it in 5-6 hours. I would recommend limited use of the impact as some of the nuts and bolts may be softer causing them to round off.
Two jack stands, a floor jack and one small bottle jack will be helpful if you're replacing the rear coils. A sturdy prybar for the front lower control arms and be sure to disconnect the abs sensor cable at the front rotors before removing the coil overs. The wires are 20-22 gauge and snap very easily inside their rubber insulation.
Shoot me a pm if you get stuck.
Good luck