Reptile Scan, why because I can update the info on my laptop but the best part is to scan the QR code to update any significant info about a specific animal.
I second this. When I only had 4 animals, I used an Excel file. When I added quite a bit more last month, I started using Reptile Scan. It's very easy to use and it's pretty cool having QR codes on my tub tags to scan and update everything at the push of a button.