Agency owners: Hiring a full-time designer vs. sticking with white-label partners?

My agency (we do mainly PPC/SEO) is at a crossroads.

We've been using a mix of white-label freelancers for all our client design work (landing pages, creative, etc.). It's been fine, but we're growing, and managing 3-4 different freelancers is becoming a communication bottleneck. Sometimes the quality is inconsistent.

I'm thinking about hiring our first full-time, in-house designer.

The pros are obvious (full control, better integration with the team). But the cons are scary (a full-time salary, benefits, training, and what happens if we have a slow month?).

For those who've been here:

• At what point (e.g., $X in revenue, or X hours/month of work) did you make the jump to a full-time hire?
• Or did you just find one amazing, reliable white-label partner/agency to handle everything?

Feels like a big decision. Curious what your experience has been.