The Gmail login page updated to reflect new targets for the amount of space each account gets. The counter on that page is always counting up, and you can actually see what it is counting to. With the new update, here's the new space targets and how many days until that much space is hit by the counter on the page:

2800MB: Already reached
2835MB: In 18.22 days
2980MB: In 384 days
3125MB: In 749 days
3270MB: In 1114 days
3415MB: In 1479 days
3560MB: In 1845 days


The last target is 3560MB, which is about 3.47GB of space. But that's over 60 months (5 years) away! But they usually change the targets over time to reach them faster or slower.