I want to name my pest control company "Service Tech" would that name be infringing on a big company that does pest control trademarked as "SteriTech"? Should I be worried?
The purpose of a trademark is to identify a business, a product or a service. The trademark is used to distinguish one business, one product or one service from all other businesses, products and services.
Trademark
law centers on consumer confusion.
Consumer confusion is created when trademarks (or logos or other identifiers) are so alike that the consumer can mistake one for the other. This is more likely when not only the marks are similar but the goods or services being offered are also similar.
If there is no consumer confusion created, there is generally no problem.
That said, it is the trademark holder who is responsible for ensuring no one infringes on his rights by using a mark that is the same or similar. Some trademark holders are more vigilant than others in policing the marketplace for possible infringers, and some trademark holders are more litigious than others.
In other words, if SteriTech thinks your use of Service Tech is a problem, it becomes a problem for you. There is a greater likelihood of SteriTech thinking your mark is a problem if you are both operating in the same geographic area because you are both in the same pest control business. You could find yourself the recipient of a cease and desist letter if SteriTech feels its mark is being threatened - or you could be sued, if SteriTech has evidence that consumers have been confused by your use of Service Tech. How a court would view this is something I can't tell you. It would depend on all facts.
You can run it all by an IP attorney in your area, if you are concerned about the risk of legal action being taken, or you can pick a name that is unique to your pest control business - one that sets your pest control business apart from SteriTech and all others. This is the route I would generally recommend taking, but it is your choice.
Good luck.