With routers the bits usually dictate the need for collet sizes. If you want to use a template to rout a worktop join you need 1/2". I think that's why most carpenters end up with three routers minimum. The 1/2" is too heavy for a lot of edge work but works well in a table, especially if you're using heavy duty profile blades. 1/4" is perfect for hinges, slotting in edges or biscuit jointing, profiles on shelf edges etc. Palm size for laminate trimming, rounding corners.
With routers the bits usually dictate the need for collet sizes. If you want to use a template to rout a worktop join you need 1/2". I think that's why most carpenters end up with three routers minimum. The 1/2" is too heavy for a lot of edge work but works well in a table, especially if you're using heavy duty profile blades. 1/4" is perfect for hinges, slotting in edges or biscuit jointing, profiles on shelf edges etc. Palm size for laminate trimming, rounding corners.