For a solo remodeler, the decision to hire usually comes down to one signal: turning down jobs consistently because there's no capacity to take them. That's the point where the math on a first hire - even part-time - starts to make sense, since the marginal job that hire enables typically covers their cost several times over.
The practical first hire for most remodelers is either a second set of hands on the tools (freeing the owner to sell and manage more work) or someone handling admin and scheduling (freeing the owner's time for higher-value work). Either way, the marketing system that keeps leads flowing needs to already be solid before adding payroll - a hire made to handle growth that isn't actually there is the fastest way to strain a small business.