Many areas of the UK have very few posted waymarks at the moment. In such areas it's quite easy to spot a new waymark as long as you're familiar with a few categories. Once all the obvious ones have been posted it will become easier to visit existing ones than find new ones; so the focus will naturally move to visiting.
Hopefully, waymarks within categories will become more straightforward to download to a PDA which will tip the balance further on the side of visiting.
I've recently posted a couple of visits on waymarks that I thought would be new posts, but turned out to already have been posted. As time goes on this will happen more and more.