Subscription licenses provide full use of Geneious Pro for the duration of the subscription (e.g. 6 or 12 months). Support and upgrades/new releases are included for the same duration. Thereafter you may opt to renew your subscription at the then current prices.
One-time purchase means you can use Geneious Pro forever. Support and upgrades/new releases are included for the first year. Thereafter version upgrades are 20% of the then current list price for the same license type.