Thanks, makes sense! A gameplay question: at which point do you allow characters to gain weapon proficiency? Do you tie it to certain events or perhaps character level?
Proficiencies require training time and money. So it can happen anytime they gain the money to do so. However, due to other expenses, they often have to decide as a group when and who will get to train. This means they might have to sacrifice buying that new plate armor or living in a cheaper room. plus its usually a great risk to adventure long enough to gain the required coin to afford to train.
As a DM, you can give this as little or as much extra flavor as you would like.