Shifting a balance from one card to another isn't recorded on your credit file, so you're free to balance transfer as many times as you like. However, a footprint is added to your file every time you apply for a new credit card.
Multiple applications, especially close together, and high outstanding debts, even at 0%, can affect your ability to get further credit. See our Credit scores guide for full information.
The most important preventative measures are to spread card applications out and use our eligibility calculator to check your chances of acceptance, before applying blind.
If you've a current 0% deal that's ending and you've a need to transfer the balance again, the best time to apply is roughly six weeks before. Use our eligibility calculator to see which card you've the best chance of getting. This gives you enough time to apply, find out if you've got the card, and shift the debt, while your other card is still at 0%.