Workers compensation is where a growing business most often finds out it crossed a line some months ago. The rules are not complicated, but they are not uniform either, and the version that applies to you depends on what you do.
Two different thresholds
For most non-construction employers, the requirement begins at four or more employees, counting full and part time. For construction, it begins at one. That single difference is the thing to carry away: a two-person roofing outfit is in scope where a two-person shop generally is not.
Agricultural operations run on their own thresholds again, and out-of-state employers working in Florida have their own rules. If your business sits near any of these lines, the safe assumption is that it is worth ten minutes of checking rather than a year of hoping.
Exemptions, and what they are not
Officers of a corporation and members of an LLC can file for exemption from coverage, within limits on how many and subject to different rules in construction. What an exemption does is remove that individual from the requirement. What it does not do is provide any benefit to them: an exempt officer who is injured on a job has no workers compensation claim to make, because that was the point of the exemption.
The other thing an exemption cannot do is cover a subcontractor. If you hire a sub without their own coverage, their employees can become your responsibility, and that liability generally arrives with an audit rather than a warning. Collect certificates before the work starts, and send us the ones you are unsure about.