The job is keeping the tire on the road
Suspension gets described as ride comfort, which undersells it badly. Its actual job is holding the tire in contact with the surface over an imperfect road.
A worn shock lets the wheel continue moving after a bump instead of settling it. For a fraction of a second the tire is carrying less load than it should, or none at all, and whatever grip it was providing is reduced for that moment.
On a dry road that is a comfort issue. On a wet one it is a braking and steering issue, which is why this matters more in a climate like this one than the word "comfort" suggests.
Carrying and towing accelerate it
A pickup used as a tool rather than as transport works its suspension considerably harder, and that applies to vans carrying stock and equipment as much as to trucks towing.
Weight compresses the suspension toward the limit of its travel, where components work hardest. Add unpaved access roads and the wear rate rises again. The interval for a vehicle doing that work is shorter than the one in the manual, which is written for average use.
Why it shows up as a wet-road complaint
The national suspension repair page covers the symptoms. What is worth adding is where drivers here tend to notice them first.
Worn suspension rarely announces itself on a dry road, because there is more grip available than the vehicle needs. It announces itself when there is not: a vehicle that feels secure in summer and unsettled in the wet, over the same roads at the same speeds, is usually not reacting to the weather. It is running out of the margin the weather removed.
That is a reason to have it looked at before a wet season rather than during one.
Why an alignment keeps moving
The last item is the most common route to a shop, usually arriving as a complaint that the alignment was done badly.
Worn components let the geometry shift under load, so the vehicle is correct on the rack and incorrect as soon as it is driven. Replacing what is worn and then aligning is the only order that works, and alignment is offered at this store, so both happen in one visit.
About this store
The Monroe store is the only Purcell location in Washington offering suspension repair, managed by JR Webster, and carries all nine Purcell tire categories.
See the national suspension repair page for all 34 locations.