If it's a gradual change over the night, I find that every 3 or 4 frames I end up moving about a quarter to half board left, depending on the number of bowlers playing the same line I am, etc.
A sudden change in lane (or more often, a sudden change in the bowler) may require one of a couple things:
If you're on a normal house shot, move left , get some head oil. Or, if you have a decent amount of oil outside and no-one's been out there all night, maybe move feet and line farther outside to get a fresh shot.
On a tougher shot, gutter to gutter, out of bounds, sport, etc., Use the 5-3 method, i.e. move your feet 5 boards and your target 3 boards in the direction you moved your feet. Fine tune your adjustments from there.
