I do the figure 8 routine each cast - whether I see a fish following or not. Thought is that there could be a fish following or close by, but not yet visible. When I do have a fish following, I keep the lure moving even for a bit after the fish seems to have moved on.
One of mine from this September was caught right at boatside during the '8'. Saw her coming in and left the lure in the water and kept it moving. She nailed it during one of the turns - so the quick change in direction could have triggered the strike.
The 49" Patsy caught last year was a fish that followed my lure in. Went past once and was out of site, but I kept the '8' going and she came back. Went past my bait not once, but three times before she headed to the back of the boat - right where Patsy was finishing reeling in a cast and WHAM.
Ya just never know.