Let’s say you want to start a small business. You could pursue traditional financing, but you could also turn to credit cards — especially if start-up costs are expected to be very low. You could then apply for a business credit card like the CitiBusiness credit card. Or you might think it’s a good idea to use an existing personal credit card instead.

Is it really a good idea to use personal credit cards for business use? The appeal makes sense. You could earn more rewards points for example. It’s easier. You don’t have to add another credit card to your personal credit history.

There are downsides to using personal credit cards in this way too. Here are four reasons you might want to consider not using your personal credit cards for business reasons.

1. Business problems can damage your personal credit history.

If you use personal credit cards for business expenses and then the business goes under, you might be left with no way to pay the credit card bill. That will severely impact your personal credit history. It’s usually a better idea to keep personal and business finances separate.

2. You decrease the availability of personal funding.

If you use a good portion of your credit limit on a personal credit card for business expenses that doesn’t leave you with available financing for personal purchases when you need it. And by running up large balances in the start-up phase with the intention of paying them off over time, you affect your credit-to-debt ratio. That might stop other credit card issuers from granting you another personal credit card when you apply because it looks like you already have more personal debt than you can handle.

3. You might lose access to credit card perks.

While you might think it’s a good idea to use your existing frequent flyer credit card for business costs so you can earn more points for business travel later, you might not get as much as you hoped for. For example, many of these cards come with free travel insurance. However, these insurance policies tied to personal cards may not cover any business-related property or situations.

4. Your records might become muddled.

If you use a single personal credit card for both personal and business-related purchases, you’re combining your financial records. That might make it more difficult when tax time comes around and you’re trying to verify business expenses with your statements and receipts. In this sense it’s better to stick to a business credit card where records are separate from personal finances and better suited for business use.

While there might be some benefits to using personal credit cards for business expenses, the downsides will usually outweigh them. Consider getting a business credit card if you must buy on credit and can’t secure other financing. If you still insist on using personal credit cards try to use a separate card for business expenses, keeping personal purchases on another card.