It can be tiered, where more training allows you to do more. On the lower end you have unarmed police giving parking tickets or having to be accompanied by a mo

It can be tiered, where more training allows you to do more. On the lower end you have unarmed police giving parking tickets or having to be accompanied by a more highly trained cop who is performing less critical roles. More training is more pay and benefits, and they have to keep it current by reapplying and showing they've done recent training, like teachers.