This will save you a lot of searching and time

When you deal with a company, generally, you deal with one person there. 

So say you have a question that you want to discuss with this company? What you need to do is get the contact information for that person. Well, you can look at your business card list, which takes time and mucking around. 

Here is a better idea when you get the business card. Call up the company in the creditor section of your POS software. Then add the person's details in the contact section.  You have a lot of space there, so if you need a few, you can add them, eg. 

Accounts Mary 038503186 | Sales  John 0415423787 | 

Now when you need to call, go to your computer, and get their details instantly.