Welsh tipper question

I see a lot of semi-bulk alloy bodied sleeper cab 8 x 4 tippers from Wales for sale .They are usually high-spec for what they are .
What sort of work have these motors been doing . Is it hard work off road on landfill sites or mainly road work .
In short have these type of 8 wheelers had a hard life that would best be avoided or would they be worth a look.
Thanks.

A lot are for sale because the rate for the work is no good,due to rising costs and no increase in the rates.