First of all, you can only use the ® symbol once the trademark registration has been successfully completed. A failure to comply with this policy may result in a fine for misleading or improper use. This also applies to the use of this symbol in commercial activities outside of the countries in which the trademark has been registered. For example, if you register the trademark in the UK and use the ® symbol alongside your brand logo in commercial dealings in the US, this conduct is subject to a legal fine.
At the same time, the use of the ® symbol is not compulsory, meaning that if you have registered your trademark, it is up to you whether or not you will use the symbol. Its use is however recommended to communicate the level of brand protection, discouraging infringement attempts.
The symbol of a registered trademark (®) should be used immediately following the use of this trademark. It is a common norm to depict the symbol in superscript in the upper right hand corner. The placement in the lower right hand corner is however also used for graphical elements (e.g. NHL or Twitter).
It is recommended to use the ® symbol with the first mention of the trademark in any publication or material. Continued use of this symbol is not necessary but it is up to the discretion of the trademark owner.