Today's newsletter mentions the great number of caches in some areas.
I have had this discussion with other geocachers who wish to hide a cache near their base of operations but thee is no space left.
Maybe the topic has been discussed in a forum and I have missed it so I will take the risk of openign the topic again.
I am in this situation where I live. My 'not thouroughly thought through' suggestion is to have some rule, or policy, such as having a cache withdrawn, either by the owner, or automatic delisting, if a cache has not been logged for a year or more. This will then free up a space for a new cache.
