Leave after 1 year at Big 4?
If you are contemplating whether or not to stick it out at a Big 4 Accounting firm. You'll need to considering one question.
Are you planning on building a career in accounting?
If you are, then the general consensus is that you should stay at least until you make senior. On the flip side, if you aren't planning to be in accounting, then it really doesn't matter if you stay three years or one month.
Though it is really highly recommended that you stay until you make manager. But let's focus on your first few years first. For most firms, including E&Y, KPMG, and Deloitte, being promoted to senior means you worked for at least two years. PwC historically has typically required three years of service before you get promoted.
The reason the industry says that you should at least stay until senior is that they employers want to see that you actually got promoted. Also, as a senior you manage associates and have to coach them through their procedures. By the time you become a senior, you'll have tested a lot of different areas of the balance sheet and income statement including the more risky areas like revenue. This gives you more exposure to the different areas. All the while you are also building crucial business skills. These skills make you highly desirable to the market.
But is it crucial to stay until you make senior. What actually happens when you leave after your first year?
Many of my colleagues left Big 4 accounting after their first year. Heck, there were some that left after three or four months. Fast forward a couple of years and looking at where they are, I'd say most have since been promoted to a senior position. Essentially, you could say that you would've arrived at the same place had you decide to leave after your first year or after you made senior. However, I'd argue that you definitely didn't learn as much in industry versus in public accounting. That experience itself may give you the slight edge over one who hasn't been exposed to as much.
Take it with a grain of salt or however you'd like. My advice is to stay until senior if you are looking to be in accounting. If you really want that big jump, it comes when you make manager.