When I started Veloviewing in the summer I decided that a 25x25 square and cluster of 1000 were good targets for the year.
And I've now achieved them (actually 27x27, as I decided to knock off all the off-road tiles around Cricklade in one go). Of course most of this has been infilling between pre-Veloviewer rides and my total tileage has only increased by ~150, but it has meant that I have visited lots of places which I wouldn't have done otherwise. Of course there are good reasons why I wouldn't have wanted to visit some of them (Tadpole Garden Village, anyone), but there have been plenty of unexpectedly pleasant ones as well.
Expanding the square any further means going further into Swindon than Tadpole Garden Village, so I won't do that until I have good reason to go there (the only good reason to go to Swindon is to catch the train out). But there are still mini-clusters to attach to the main one, so I hope to add a few more tiles to the cluster total.