Although you have submitted a product registration that just flew through the FDA or Japanese PMDA without questions, all your registrations need to be maintained. And it is important to remember at both the times, i.e., when you initiate a registration in a particular region as well as yearly when you plan the resources.
Firstly, you need to be aware of how often each market requires re-registration and how complex they are. It can be anything from just submitting your quality certificates all the way to onsite audits on your manufacturing sites. Also, the length of the re-registration process is important to be known, as you need to know when the work needs to be started.
Additionally, you must keep track of any changes in the regulatory requirements of the market in question. There can be changes both in registration requirements as well as changes that need to be reported and/or updated in vigilance reporting requirements.
This brings us to the topic of changes. When you are on multiple markets, your change procedure must include a mechanism for what changes need to be reported to authorities as a change notification or if re-registration is required. And as always, this assessment must be documented in connection with the change.
As you can see the QA department needs to be appropriately staffed if you intend to be on multiple markets. Also, you need to have discipline on device changes so you are not making small, but significant changes continuously that will require a multitude of submissions. This is often the case with software changes. It is better to introduce several changes simultaneously and report the changes in a single submission. That will save a lot of work. But planning is the key.
But with proper planning your company will enjoy the fruits of your gardening for a long time.