Tough question and it just depends on your marketplace and your financial situation. Your Realtor can help you decide this. Some of the questions I would ask you are:
1. Can you get a loan for two homes at the same time or do you have cash to pay for both?
2. Can you make two house payments and for how long if you get a loan?
3. How long will it take to sell your current home?
4. How difficult will it be for you to find a new home? Will you look at 3 and pick one? Or do you need to look at 100 to find the needle in the haystack?
5. If you sell first, do you have a place to go in the middle between your sale and purchase? Can you live with relatives or in a hotel?
6. Be careful these days about trying to close on the same day. It can happen, but with the difficult situation with buyers and lenders there are often problems closing on time. If your buyer can't close on time, that may put your new house and your finances at risk.

That's hard to answer without knowing your specific financial situation.

The question you should be asking yourself is: Can I **afford** to have 2 house payments?

In most cases, I would advise against it simply because that very move has placed many people in some pretty dire financial circumstances.

However, there are some that can afford 2 mortgages and have the freedeom to buy first and sell later.

Just keep in mind the additional expenses in maintaining a second home. As an example, when you move out, that property will no longer be your principal residence and therefore will not qualify for a homeowner's exemption on property taxes. Depending on how long it takes for you to sell your 1st house, it's another expense that can impact you financially.