William Smith and Reino Talarmo are correct, plus setting the account you use on a daily basis to a standard account CAN mitigate many types of infections as long as you don't type in your admin password unless you know you want said application to have admin access.

You can setup a separate admin account without actually logging into the account there by negating any wasted space but even then the space used is so minute I wouldn't even worry about it. You're talking about MegaBytes of space, not even a Gigabyte by any means.

You can keep your user account that you will be using a admin account while you set it up. Once setup create a separate user account that will be your admin account that requires a password for anything further that requires administrative privileges and then change your personal user account to a standard account.
When you try to do anything that requires administrative privileges you will be prompted to put in a administrative account password.

This is something I did with my kids laptops (I use Linux) and it helped keep out unwanted guests (at school) and stopped a couple potential infections from taking place.
It's sometimes annoying but when it keeps a infection from taking hold and/or keeps a unwanted user out it makes it worth it.