In Euro Truck Simulator 2 and American Truck Simulator, there are a plethora of drivers to choose from. It all depends however how many truck dealers and recruitment agencies you discovered and how many garages you bought plus how much garage space you have. Each driver requires the following:
1 - A Truck to Drive.
Note: If they do not have a truck to drive after one or two days, they will email you saying they need a truck or they will leave you within 2 - 4 days.
2 - A Garage space for them.
For the trucks, it does not really matter what upgrades and cosmetic upgrades you give to your drivers. As long as they have a truck, they will work for you no matter what.
Skills and Wages Edit
Each driver has a set of skills and also wages. The better the driver, the higher the skills and wages will go up meaning more income towards the company.