Should I switch to the 6% simplified tax system if my income has grown to 2 million a year?

You can work under the 6% simplified tax system up to 2.4 million a year, so technically you're still within the limits. But the question isn't about the letter of the law - it's whether this system actually works for you at that level of turnover.

At 2 million rubles in income on 6%, you'll pay 120 thousand in taxes a year - that's a lot. If you have significant expenses, it might make more sense to switch to the 15% simplified system (tax on profit) or even stick with the standard system if your expenses are high. Here's a typical calculation: add up all your costs (purchases, services, salaries), subtract that from your revenue, and see what you get with a 15% tax on profit. Often with high expenses, that comes out cheaper than 6% of the whole amount.

Another important thing - check the restrictions on the 6% system: usually you can't hire a lot of employees and you can't work in certain industries. If you're already getting close to those limits, it makes sense to think about switching ahead of time so you don't run into trouble later. Talk to an accountant; they'll figure out your numbers in half an hour and give you a straight answer on whether to switch or not.