What size SEO company is best for my business?
The best size is the one whose capacity matches your workload and whose structure gives you the access you need. Size on its own predicts less than it seems to: a small firm can be stretched thin, and a large one can give a small client close attention. So rather than choosing a size category, work out what your engagement needs, then ask each company the questions that show whether its size, and the way it uses it, fits.
Four things that decide the fit
The first is the volume and spread of work. A site that needs steady content, technical work, and link outreach across many pages needs more hands than one that needs a focused set of fixes. A firm should be able to explain how many people would work on your account and what each would do.
The second is the number of channels you want handled together. If you want SEO coordinated with paid search, social media, or website development, a company that covers those in-house saves you coordinating several providers. If you want SEO alone, breadth matters less.
The third is access to experienced people. Decide how much it matters to you that the people you meet in the sales process do the work, or at least direct it. Then ask who will run your account day to day and how involved the senior people will be after you sign.
The fourth is continuity. With very few people, the loss of one person can stall your account. With many, your account may pass between people more often. Either way, ask who backs up your main contact and how knowledge of your account is kept when people change.
Two questions that measure attention
Ask how many other accounts your main contact handles. A specific number tells you more about the attention you will get than the size of the company.
Ask what share of the work on your account would be done by subcontractors or freelancers. Using outside specialists is normal at any size, but you should know who is doing what.
Size and price
Larger organizations carry more overhead and may set higher minimum budgets, while smaller ones may not have the capacity for a large scope. Neither rule holds every time, so compare proposals on what each commits to for your site, not on the size of the company sending it.
A simple way to decide
Write down how much work your site needs, which channels you want handled, how much senior involvement you expect, and how much disruption you could tolerate if your contact left. Then ask each company to answer those four points for your account specifically. The company whose answers match your list is the right size for you, whatever its headcount.