Use of a trademark
If your trademark is registered, the idea is, of course, that you actually start using it as well. If you fail to do so for a period of more than five years, your trademark will be liable to revocation (entirely, or for some of the goods or services to which it was intended to apply).
In this context, you should make sure that you use your trademark as you have filed it. If, for example, you update your logo, a new filing will be necessary.
The use of an ® sign can make it clearer to third parties that your trademark is registered.