When to bring in the heavy hitters (2017)
There's only one real answer.  It's when you're ready to be a big company.  But not just because you want to be a big company.Heavy hitters (i.e. former executives of big companies) bring big company expectations.  They expect to hire a big team.  They expect that your product is ready to scale, and in B2B, ready to be packaged and sold down a channel.  They expect that you know how to sell your product in a repeatable way, a way they can copy, optimize, and teach to new hires.  They expect to move at a big company pace, and expect you have some semblance of big company processes.These people, in general, do not know how to, and do not want to, live the kind of startup life you've been living -- the hours, the apparent chaos, the extreme frugality, the wearing of many hats.  They won't love your product like you do.  This will be a job for them.Remember that they're almost always from big companies, but much less often did they help build those companies at the critical juncture -- the time before everything was working.  The time before it was clear the company would succeed if it could just expand on what it was already doing.These heavy hitters mostly expect that your company already works, fundamentally, and that you're hiring them to do more of it.  If that doesn't sound like your company, you're not ready yet.And if you hire these folks before you're ready, it will probably destroy the company.  It's a one-way function.  By their nature, they'll drive out your early hires and scale your costs.  If your revenues don't scale comparably -- because you didn't actually have product/market fit -- then those heavy hitters and the teams they brought on will leave when they see the writing on the wall.  Leaving you, alone, back at zero.