One of the more useful things about a modular wardrobe system is that day one doesn't have to be the final answer.
The short answer
Yes. Shelves, rods, baskets and other compatible accessories can be added later, subject to the available layout and system compatibility.
How to leave room for it
- Keep one bay lighter than the rest at installation — it's the easiest place to grow into
- Decide hanging length first; folded storage is simpler to add afterwards
- Tell us at the site survey if you expect the room's use to change
What we'll need from you later
A photo of the current setup and a note about what you'd like to add is usually enough for us to check compatibility and advise on the options.
Bottom line: start with what you need now. Adding on later is part of how the system is meant to work.