...when it's easier to sell them on?
Just having a quick total up and:
2 x Panasonic G520's - one went to my mother, then recycled by Vodafone, one sold on to a workmate.
2 x Panasonic GD93's - one kept and is my backup/backujp handset, one sold on to a work colleague (who then lost it in Sainsbury's)
2 x Panasonic GD87's - both sold on to workmates.
2 x SE-V800 3G's - one traded in at CEX, one sold on eBay
2 x O2 XDA mini S - one sold on eBay, one kept for the Wi-Fi browsing when abroad.
The mantra is reduce, re-use then recycle.