In the strategy that is hiring, you should anticipate this. Startups intend to over-hire in sales, but not in other sections. What’s this? It is because AE hiring is directly connected capacity and thus growth. A mis-hire may cost the company $500k in ARR, which can be the difference between developing 2x and 2.5x at the early phases. Therefore it matters.
A vital component will be the hiring strategy, as you build out your startup’s fiscal model for 2019. You will want to calculate the quantity of managers and individual contributors to achieve your goals. But don’t forget to plan for mishires.
You may make mistakes. Most of us do and it is part of building a firm of this process. Someone looks great on paper but isn’t a culture match. Another will not ramp enough. A third might not possess the work ethic. Whatever the reason, it is going to occur.

No matter your quote, take the time to consider over-hiring from the GTM and encourage teams to make sure you’ll have the capacity to support your client base that is growing.
There’s no way. 20 rate, and it is a good estimate is projected by businesses.
Overhiring in other GTM teams such as customer support, client success, sales technology should be considered, particularly if the company is hiring fast and on a steep ramp; and the business has got the balance sheet to support this approach.