Always be recruiting
In sales, there is an old expression: "The toughest time to make a sale is when you really need one."
Source: Sales consultant/author Lee Salz
The same holds true for recruiting. When a slot is open on the sales team, it becomes an all-hands-on-deck exercise to fill it. While the seat is open, revenue targets are in jeopardy. This leads many to forget the profile of the ideal sales person profile in the interest of filling a seat. Playing this forward a bit, the seat becomes vacant again a short time later when either side determines that it is not a good fit.
Sales recruiting is a year-round exercise. The best sales forces are always on the lookout for strong sales talent. Find a company that identifies a strong candidate that meets their profile who wouldn't find a way to hire this individual. It is a rarity to say the least.
Sales teams have turnover either driven by the company or the employee. It is best to have a candidate portfolio at the ready than to begin a process of surfacing candidates when a seat is open. Poor hiring decisions are made out of desperation to fill a seat. The open seat is a cost to the company every day it is unfilled. Yet, the cost is more painful if the seat is filled by someone who doesn't fit.