A home and building are different structures with different setups. So when it comes to doing electrical work on them, you should be prepared for how each type of layout calls for different skills to be used to complete the job.
If you're planning to work primarily as a residential electrician, then your training will be focused on things like grounding, circuits, air conditioning, appliance systems, and motors. For commercial training, you'll learn more about voltage systems, computer cabling, generators, and surveillance cameras. You'll need to be ready to upgrade entire wiring systems. There is some cross-over tasks for sure, but there's a distinct shift between how you approach each set of problems depending on who needs what.
Electrical issues come up everywhere, so if you're good at your job there's no doubt that there will be work awaiting you almost immediately. However, larger structures tend to need a lot more work than a simple single-family house. Homes only run on so much power, while huge corporations risk blowing a fuse (or ten) because of all the computers and equipment sucking up electricity. They also require more upgrades and additional maintenance much more regularly. A family is only likely to call an electrician when the house has a large issue, while a corporation might need someone in on a monthly basis to do regular check-ups.
Jack Of All Trades
It would be nice if you could be able to perform every kind of electrical work. And actually, some electricians do manage to do that, through many years spent perfecting their trade.
If you're planning to be a general electrician, then you might want to think about starting your career with residences and moving over to commercial or industrial projects once you have mastered residential electrical work.
Take extra courses in commercial while working as a residential electrician. This way, you get a chance to appreciate the smaller jobs and learn where there are fewer complications.
Technology affects all of our lives on a daily basis, and it's amazing how quickly things can go from being difficult to being simple. If you choose to specialize in one field over the other, you have to be reasonably sure that it will sustain you for many years to come. You want to feel confident that you still have the skills to support yourself and your family if something changes.
On the plus side, specializing in certain aspects of the electrical field, particularly as technology continues to change and evolve, will open up new and different opportunities throughout your career.
If you know you want to become an electrician but are undecided on which area to focus on, don't let that stop you from getting into classes. You will know what to do when the time is right, and you definitely don't have to immediately decide.