One of the best pieces of business advice I ever got came from an adviser: 'The secret to creating a valuable company is to find something you can build once and sell many times.'

The advice sounded so simple but was devilishly hard to implement. At the time, I had one of those nasty businesses that required a custom proposal for every job. Each client wanted something unique, and the variety and complexity of their requests meant that I would personally have to review pitches. It seemed like we spent more time writing proposals than actually doing the work.

After a while, we finally decided to focus on one consistent subscription to our research and conferences – build once, sell many times. We created one brochure and stopped writing custom proposals. At the time, I thought the biggest hurdle would be convincing my customers to stop asking for modifications and special exceptions.

As I rolled out our new focus, I found our customers to be the least of my worries. Most clients embraced our focus and willingness to commit to an area of specialization. What I didn't expect, and what actually became the biggest hurdle in making the switch to a scalable business, was the resistance coming from my employees.

My employees wanted to focus on what they found intellectually challenging, which usually meant our custom jobs.

I hired one sales rep right out of business school—we'll call her Sabrina—who was a problem from day one. I'd send Sabrina out to sell our subscription service, and she would come back and insist we meet one-on-one because the prospect represented a unique opportunity. Not wanting to quash her enthusiasm, I would agree to sit down with her, and each time Sabrina would lay out a problem with a prospective client that required—in Sabrina's mind—a truly custom approach.

Each time I would patiently explain to Sabrina that we no longer offered custom consulting and special tailoring for each client. I would point out that her prospect's issues were actually not all that unique and could be satisfied by our standard offer. With each explanation, I would get increasingly firm with Sabrina. Finally, after six months of wasted effort, Sabrina and I agreed it wasn't working, and she left.

I ran into a similar problem with one of my senior consultants, whom I'll call Riley. Riley had come to our company from another consulting firm and was always determined to prove himself the smartest person in the room, which is why he would go way beyond our standard offering when serving our clients. If our contract with a customer promised two workshops, Riley would do four. If a client wanted some extra analysis done that fell outside of the scope of our agreement, Riley would offer to do it.  This made for great client relationships but also meant we couldn't give Riley as many clients to manage as our other consultants.

I don't think Riley or Sabrina were bad people or unintelligent. In fact, they were among the most educated—and expensive—employees we had.  I actually think they were overqualified to work in a company that wanted to scale up. We needed people to follow systems, not to reinvent them.

Next time I'm going to save myself both the money and hassle and hire fewer people who want to think and more people who want to do.

John Warrillow is the author of Built to Sell: Turn Your Business into One You Can Sell. He has started and exited four companies. Most recently John transformed Warrillow & Co. from a boutique consultancy into a recurring revenue model subscription business, which was acquired by The Corporate Executive Board. In 2008 he was recognized by BtoB Magazine's 'Who's Who' list as one of America's most influential business-to-business marketers.