4th gear vs drive

I have a 2009 Toyota Camry SE and I do plenty of city driving going up and down hills mixed with freeway driving. I was wondering when I should use the 4th gear vs drive. Any insights are greatly appreciated and thanks so much in advance!

Check your manual. Stay in drive except for those few occasions you need engine braking, or limit hunting at speeds less than 35 mph with hills. If you struggle with understanding the difference as pointed out in the manual, leave it in D(drive) all the time and pay a little more for brake servicing. That’s the easy way out and better for your car if you don’t have confidence in your understanding of the manual.

Use drive unless there is an unusual driving situation where it is desirable to lock out 5th gear. If your car needs to be in 4th or even a lower gear, your transmission will automatically shift to that gear while in drive.
The only good reason to lock out 5th is if you are going down a long downhill stretch of highway and leaving it in drive makes you endlessly ride the brake to keep the speed in check. Locking out 5th gives you more engine braking in that situation.
It’s called an automatic transmission for a reason.

If you happen to be cruising along at just about the 4th/5th shifting range, or you notice the transmission downshifting into 4th a lot like on a hilly stretch of road, locking out 5th can save you some transmission wear and tear.