I once had a manager who would often tell us, “You know, as they say back in my home state of Indiana, you gotta make hay while the sun shines.” This was a man who’d be wearing $300 Italian loafers and a $500 Hugo Boss sport coat, so it was a little hard to believe he learned this aw-shucks wisdom on the farm. It stuck with me, though, because I use that phrase all the time.

“Making hay while the sun shines,” which sounds like a euphemism for getting it on in the daytime, actually means to make good use of an opportunity while it lasts. In the days before modern farming equipment, farmers literally had to “make their own hay”: they had to cut, dry, and gather it by hand. Hay is ruined if it’s wet, so if the day was hot and dry, well, you gotta make hay while the sun shines.

This saying is incredibly relevant in business, especially if you’re in sales. If you have a prospective customer, the best time to sell is as soon as the customer approaches you. Let me share two quick stories to illustrate my point.

A year ago, we were developing a new ebook product for Media Shower. (An ebook is a 15-page downloadable PDF that companies can offer from their website, as opposed to a short-form blog post.) I did a search and found that the inbound marketing company HubSpot had a free downloadable ebook template. I downloaded the template to check it out, giving them my junk email address — the one I use when I don’t want to be bothered.

Within thirty minutes, I got a call by phone from a HubSpot sales rep. This means she was immediately alerted about the download, got my junk Yahoo email address, figured out our real company on LinkedIn, tracked down our company number, and found her way to my phone.Thirty minutes!

Here’s the second story. A few months ago, I was shopping for jewelry for my wife for our wedding anniversary. I was shopping online jewelry vendors, and heard good things about a company we’ll call Zarathustra. I called them up, and spoke with a very knowledgeable guy who took all my information and said he’d call back with a quote. I never heard from him again.

As our anniversary loomed nearer, I called back Zarathustra several times, and got a general voicemail box. I left messages, but no one returned the call. So I went to a local jeweler instead.

Three weeks later, I got a voicemail message from a woman at Zarathustra who wanted to see if I was still interested in the jewelry. Three weeks!

Selling is a funny thing: as PayPal founder Peter Thiel has pointed out, we don’t want to be sold something, unless we want to buy it. No one likes a cold call. Salespeople are an annoyance … unless we’re already interested in buying.

When your customers are ready to buy, the time to sell is right now. Not three weeks. Not tomorrow. Not even after lunch. It’s interesting how fast customers lose interest in buying: either they’ve found another company, they’ve found an alternate solution, or they’ve decided they don’t need it.

As marketers, we’re responsible for getting customers to make that initial contact: downloading the ebook, calling the sales line, requesting a quote. How fast does your sales team respond? Test your own company’s response rate: use an anonymous email and see how long it takes someone to get back to you. Marketers can get people into the sales funnel all day long, but it doesn’t do much good unless that funnel is greased and slippery.

The best time to sell is as soon as the customer wants to buy. Strike while the iron is hot. You gotta make hay while the sun shines.

Sir John Hargrave is the CEO of Media Shower and author of the upcoming book Mind Hacking. This post is free to distribute under CC 4.0: if you like it, share it.