Yes you'll stop. Nobody can lift a house. :)
If you are as functionally fit as you wish to be, you will focus more on maintaining your lean body mass than on building new mass. This is a time where, if you increase at all, it will be very slowly. You will probably do a pretty similar workout most workouts, with little to no actual increase in reps or weights.
If you're not there yet, keep plugging the weight up!
And if you want to increase strength, keep plugging it up. As in the house analogy, you can't keep increasing weights forever, but you'll find the increment of increase slows down. Eg at the start you might increase the reps every workout and the weight every month. By the time you've become quite strong, you may be increasing reps every month or two months, and weight every 4-6 months. Or increasing weight in 1lb increments instead of 10lb increments. :)
Deb, in New Zealand