I've been mapping for this project now for just over 10 months and sometimes I am surprised at how complete the map now seems compared to when I first looked at it. I know I've done a lot of work near where I live, but I tend to look at that in isolation and know how much there is that can still be added (as I drive around there are lots of public footpath signs that seem to jump out to say "You haven't walked me yet"). But I sometimes forget that there are many other mappers out there also working hard to improve their localities. Colchester is so very much better as well for example, and I've only been there a couple of times to map (usually to walk cycle routes).
What made me consider this was that I did a two hour round trip on Saturday to add three nodes to the map. Admittedly they were very specific nodes (NCN mileposts - see http://wiki.openstreetmap.org/wiki/WikiProject_United_Kingdom_Sustrans_Mileposts) and were south of Colchester (near Birch), in the centre of Colchester, and north of Colchester (Langham), so weren't particularly close together either.
Then on Sunday I was pushing a pushchair randomly around the Beehive pub in Beehive Lane off the A12 making traces. I thought perhaps if the area had largely been traced from Yahoo (I don't know whether it had been or not) then the service ways behind houses to garages not only made for more peaceful walking, but also were less likely to be on. I think I added one small driveway, one footway, plus fleshed out the Beehive's car park details a bit.
On the way home we made a slight detour to Little Totham to visit the end of the beer festival at The Swan (CAMRA national pub of the year in 2002 and 2005). I could easily find an excuse to spend a day mapping that village, with pub lunch, as compared to the other areas I'd been in recently, my few brief notes from where I parked added the pub itself, the start of two footpaths (well one that crossed the road and ran down the side of the pub), the start of one side road with a note about another being visible off that but unsurveyed, a post box and a telephone box. I was also able to fine tune the lane to the village (NPE sourced) to the GPS trace and remove the source=NPE tag.