It can be done, but in addition to the time/exercise/weather commitment, you should also keep in mind that, out of the fraction of all rental properties that allow pets, the majority of those will still have a size limit and/or prohibit certain breeds, and the GSD is almost always on the no-go list (often because insurance companies are not friendly toward GSDs). So if you plan to move out and keep the GSD with you, you are likely to be very limited on where you can live. The pet-friendly properties may cost more and yet they are often the most run-down and undesirable. In the case of dog-friendly apartment complexes, you can often expect fleas, barking, and poop left in the grass. In certain cities where there is a shortage of rental properties, you may not find any options to rent with a GSD at all.