openSUSE .isos are rarely replaced after their original GA release. If you install with online repos enabled when the installer asks, then further updates immediately post-installation should be between 0 and few, because newer packages online will be used instead of those on the DVD .iso. If you plan to use an .iso only once or possibly twice, you should consider using the NET .iso, which takes only a small space on a CD or USB stick, downloads quickly, installs most packages from online repos, and only downloads those actually needed.