Here’s a scenario. You’ve just arrived for some birding in an exotic destination, say south Texas. You’re fresh out of the airport in Corpus Christi and on your way to, say, Santa Ana NWR. You want to get to Santa Ana and all its avian gems fast, but as you drive birds start appearing - perhaps a tempting distant raptor that might be your “life” White-tailed Hawk, or a Scissor-tailed Flycatcher keyed up on a wire fence.
It’s difficult to drive by birds, but sometimes you must. In almost any birding situation using your time wisely will mean more quality looks at more quality species.
Different birders will apportion their time differently, but one rule I sometimes apply on trips is this: focus on finding the scarce species, and the common ones will take care of themselves. A forest that has Kentucky Warblers (very scarce in NJ), for example, surely will also have Wood Thrushes. The reverse may not be true - the woodlot you hear a Wood Thrush singing from very probably will NOT have a Kentucky in it.
Farther afield, focusing on searching for a Clay-colored Robin at Bentsten State Park in Texas will likely turn up Olive Sparrows and Golden-fronted Woodpeckers. The bottom line is know the status of the birds you seek, and plan to invest the time and effort in finding the hard ones first.