I am definitely of the try, try and try view. *
In my business, over the course of 10 years, there were lots of things that worked and some that did not work, but overall the business was successful and we learned from our mistakes.
For example, when we decided to expand our aeration operation we bought a Ryan LA28 which was a sizable investment for us. We restructured the company and re-designed a lot of our marketing. However, it paid off in that we used the LA28 to sell a superior aeration job and we were able to do them more efficiently. It was a great success.
We took this one step further when we invested in a marketing campaign to sell our aeration services to other lawn maintenance companies with the idea of sub-contracting to them. This failed dismally as we found, at least in our area, that LCOs want to do their own aeration.
You definitely have to keep trying new things all the time. Watch for new technology, improved equipment and the industry as a whole and look for new opportunities. Not to say that you should throw caution to the wind and buy everything that comes along. Of course you must do your research, count the cost and plan how you intend to make it successful. If it is not as successful as you had hoped or if it fails all together then at least you walk away wiser. Chalk it up as a learning experience.