Toyota Repair: Lexus GX470 starting problem

Question
Hello - I could not find a Lexus expert.
My 2008 GX470 has 48000 miles; problem with starting is new.
When trying to start get clicking from solenoid but there's plenty of battery power for lights, etc.   I left the car for 20-3 hours, came back with a charger but it started immediately.
Same thing yesterday:  battery seems fully charged but clicking when trying to start.  Tried a few times over an hour but still clicking.  Left the car stand for 2+ hours, then it started immediately.
Although the battery is not new I don't think it's the problem.  Is this a problem with the solenoid contacts?

Answer
Yes, the solenoid is usually the problem for this, the starter/solenoid assembly needs to be replaced, this model is basically the same as the Land Cruiser, very common problem and I have replaced quite a few starters, unfortunately the starter is not easy to get to, it's located in the center of the engine under the intake manifold, repair time is about 8 hours.