There is no mileage interval to replace struts. But I can say for certain that by 178,000 miles, the best days of your shock absorbers (struts) are long behind.
I would recommend having a look for replacement around 75,000 miles or so. Remember that these vehicles and suspensions will not bounce excessively doing a "bounce test" at the four corners, no matter how the struts are. It's just that the suspensions are so tight you cannot rely on this test.
I can't speak for the integrity of the tech, but I can definitely say that he is not out of line on this recommendation. Good luck.
PS -- to push the tech at the shop, ask "are these struts NEEDED or just RECOMMENDED?" At least then, you will have peace of mind as to what grounds the recommendation is made from.