We’ve put numbers on our series to indicate that they are just that – in a series and in what order they should be done either numerically going up or down depending which way people want to walk. If you didn’t give them a number they would all have to have different names and it may be more easy to miss one on a route maybe? We used to put the number at the end and then put it at the beginning after reading somewhere several comments about it being easier to find the next cache to do when walking a route if the name starts with the number rather than it being at the end. This was because if the name is long and the number is at the end it isn’t visible immediately on some GPS screens. This may be why more people name them that way now. It was the reason we did anyway!