To get a grip on LCM it is advisable to create a year calendar that shows when assets need to be updated. This includes hardware, software, licenses and certificates. For all those assets the current version needs to be know and the current available version. The current version doesn't need to be the latest and greatest, it needs to be a recent stable version with all security updates. Alas, the newest version can break your systems sometimes, so be alert on running the newest (n) or the one before the newest (n-1).
When you have the basic information start extrapolate on the history of the versions from your assets, nine out of ten times you can find this information on the asset providers website or in a changelog. Plot out in cadence the upcoming versions.
Now we have a view on all the LCM work that needs to be done in the upcoming year. The next step is to calculate the workload on the items and get a grip on the time needed to maintain the assets. The calculation is just a sum that you and your team predict for what is needed to perform this maintenance. You end up with a table of all the assets, the predicted maintenance dates and the manpower that is needed to perform that maintenance. All maintenance can now be planned in the correct timeslot you use for planning, be it sprints or months for example.
The collected LCM information can be feed back to any roadmap plans to make realistic planning on upcoming sprints, months or quarters. You just made LCM planned work instead of unplanned or reactive work.