For a typical back yard, a fence is usually two to three working days. The number that matters more is what happens on each of them, because the order is not optional.
Before anything, the line gets walked and the utilities get located. Nobody digs before locates come back. That is not us being cautious, it is that hitting a gas or fiber line is a serious and expensive event, and the locate is free.
Day one is posts. Holes get dug, posts get set in concrete, and everything gets checked for line and plumb. Then it sits. Concrete needs time before anything hangs on it, and a crew that sets posts and starts hanging panels the same afternoon is borrowing against your fence.
Day two is the fence. Rails and pickets, or panels, depending on what you chose. This is the part that looks like progress and it goes fast once the posts are right.
Gates come last, and they take longer than people expect for their size. Hanging a gate is fitting a moving part into a fixed opening, and getting it to swing clean and latch every time is adjustment work.
Things that add days: long runs, slope, rock, heavy brush, limited access for equipment, and weather. Rain does not just stop work, it can make setting posts in soft ground a bad idea for a day after.
We would rather give you a real timeline after walking your property than a fast one over the phone that we have to take back later.