I have not done an X, but did the belt on my pathfinder - about the same v-6. Much of the time spent is involved in removing stuff that's in the way. Figure 8+ hours for a first time learning job.
Deal breakers. Impact tool for crank bolt. Puller for crank pulley.

dave without xtoy - the old belt looked like new

PS - don't allow anti-freeze or other fluids get on the belt!