It must happen before mowing, of course, but preferably sooner than that. Around here, it needs to be done every day or so, at least in the spring when strong winds rattle the oaks and do as much pruning as shears or clippers.
With every bending down and picking up, I fell myself that I'm building up a pile of kindling for a bonfire some day. Or at the very least enough to stuff a can of yard waste for the recycling pick-up next week.
Most of all, I tell myself that these are nothing, mere toothpicks, the balsa wood of yard flotsam. The big trees they came from, they're still standing. And that's what matters most.