Sure! You can download it as many times as you want whenever you want from the download link of the email you received after making the purchase. And once you start working on the template, you can email the template files to yourself (since they are just Word or Pages files) to use on any computer. Just make sure you install the fonts on each computer so the templates look as they should!

Alternatively, you can create a Gumroad account. With a Gumroad account, you are able to access your Gumroad purchases at any time through your Purchases.