Recurring service vs. a one-time treatment
Which makes sense for your situation.
The honest distinction
A one-time treatment makes sense for a specific, contained problem — a wasp nest, a single invasion. Recurring service makes sense for the ongoing seasonal pressure most homes face, because the pests come back on a schedule whether or not you do anything.
A good provider will tell you which your situation actually calls for rather than defaulting you into a plan you don't need.