Small enough to manoeuvre, but large enough to carry your load, can become an important consideration when working in busy urban environments. Car derived vans, or pick ups can be a great solution for management who need to optimise efficiency with the capacity to drop off tools and equipment short notice across multiple sites, If an occasional large load, roof racks can be a solution, or pick up hard tops can add security and protection from the elements.
For most tradesmen a 1 ton payload van typically has a pragmatic 2440mm load length and 4900mm external length, Plumbers typically prefer the longer L2 medium wheelbase and a 1.2 ton payload.
Couriers and those who need to optimise the max load volume typically consider L3 long wheelbase with either H2 medium roof or L3 high roof 3.5 ton gross vans variants.
If heavy loads or towing is a consideration, then think rear wheel drive, if low loading height or max payload then front wheel drive is your solution.