Yeah as Martin says, the amount to bevel will depend on the size of your mesh. It’s not the same to have 2 millimeters of beveling on a 210 meter size object than to have 2 millimeter of bevel on a 10 millimeter size object, on this last one the bevel would be huge and on the first one the bevel would be very tiny. So you have to judge for your object what’s the best bevel you need. Always have scale applied, so Control + A -> Apply scale and there’s a clamp overlap option on the bevel modifier that you could disable since that clamps your bevel so that the mesh doesn’t go all crazy. If it goes all crazy then get the bevel value down.
