Serial entrepreneur Robin Chase knows a thing or two about big exits.

Her most famous venture, Zipcar, the car-sharing business she co-founded in 2000, was acquired by Avis Budget Group for $491 million in 2013. (Chase had departed the company by then.) Her next car-sharing startup, Buzzcar, merged with competitor Drivy in January 2015.

In a recent Inc. Founders Forum video, Chase talks about how entrepreneurs can identify opportunities that might eventually lead to such lucrative outcomes. One useful tip: Look at spaces where 2 percent of the businesses control 90 percent of the market share.

"There are incredible economies of scale there," says Chase. "Everybody has got their weak spot, and everybody has people who they are not serving well. Go after them."

But once you've established a successful business, how do you know when it's the right time to sell? Chase suggests asking yourself these three questions:

1. Why are you selling?

The first question you should answer is why you might want to sell. Are you looking to retire, because you want to do something else? Or is the business going under and you need to make a quick exit?

2. Do you have the luxury of choice?

Once you have decided to sell, analyze your options. Are there multiple offers on the table? Or is the market about to turn and you're looking to make a profit before it's too late?

3. Does time really matter?

If the business is healthy and you have decided to sell because you want to retire, you can probably afford to wait around for the right buyer. The process could take more than a year, but you'll be rewarded with a buyer who shares your vision for the company. If, on the other hand, you need to sell quickly because the business is going under or the market is about to change, then you can't afford to waste any time. You want to sell when you still have a good amount of assets to offer.

Whether or not you decide to sell, there are two lessons Chase recommends keeping in mind: Always trust your judgment, and be honest with yourself.

Learn more about Robin Chase's thoughts on the sharing economy and entrepreneurship in the video above.