The details.
What are the four pages every small business site needs?
Home: what you do, who it is for and where you do it. Services: the specifics of each thing you sell. Proof: photos, reviews or a short about section that shows a real business. Contact: one obvious way to reach you.
Each page has one job. If a visitor lands on any of them, they should know within seconds what you do and what to do next.
Can one page do all of that?
Often, yes. If you sell one or two services in one area, a single page with clear sections beats four thin ones. Plenty of effective small business sites are one good page.
Add pages when a topic outgrows its section, not before. A service that needs its own examples, pricing or questions answered has earned its own page.
When does a service need its own page?
When people look for it as its own thing. Someone searching for deck repair is thinking about their deck, not about your whole company, and a page about deck repair speaks to them directly.
Two or three services usually fit on one page. Beyond that, give each one room.
Do I need a blog?
Not at the start. A blog with two posts from three years ago can read worse than no blog at all: it suggests the business might be asleep.
Add one when you have a steady reason to publish: real project write-ups, price updates, or answers to questions customers keep asking. A single good page that stays current beats a dusty news section.
What should I leave out?
Pages that answer questions nobody asks: a mission statement page, a gallery of stock photos, a news page nobody updates, testimonials with no names attached.
Every page costs a visitor's attention. Spend it on the ones that answer real questions.