little question

lucsfar1a First, it's good to plan ahead, so plus one on that point.

I'd say think long term. Access can carry you a long way. However, data volume is only one component. More important, IMO, are better data security, scalability and robust processing power in SQL Server.

Over the long run, most organizations can eventually benefit from those factors by migrating their data to SQL Server. But in the short run, there's not much to be gained. So, I'd say a good strategy would be to make your Access relational databases as solid and you can in the short run and begin preparing for the migration by installing an instance of SQL Server Express on your own computer so that you can begin learning how best to incorporate it. Eventually, you'll have a decision point about upsizing and being experienced with SQL Server will help you make a good decision. 

Keep in mind that whatever you do in the long run, your Access relational database applications must be split, with a copy of the interface accdb on each users' computer, and the data accdb on a network server. Your users won't experience much change in their Access interfaces if and when you do replace the data accdb with a SQL Server database as long as you plan for and prepare the transition well.