Scanning Software

I bought an Epson CX5200 and was using the s/w that came with it, beause I never had a scanner before. I realized it was lacking and installed VueScan 7.6. My question is how to make VueScan the default? Do I trash the Epson Scan sw (that is what fires up when I hit the scan button on the scanner) or do I have to start VueScan on the iMac every time I want to scan something. Thanks in advance for for any help.