We also need to bear in mind that SaaS vs On Prem also often implies 'subscription' licensing vs perpetual software licensing (one off + support payments).
If a SaaS product is $100k per year (subscription) the equivalent perpetual license cost is probably $200k (one off) + $40k annual maintenance (my very rough rule of thumb after doing lots of tenders - a perpetual license is usually two years of the subscription fee plus 20% of the perpetual license cost as support fees).
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We also need to bear in mind that SaaS vs On Prem also often implies 'subscription' licensing vs perpetual software licensing (one off + support payments).
If a SaaS product is $100k per year (subscription) the equivalent perpetual license cost is probably $200k (one off) + $40k annual maintenance (my very rough rule of thumb after doing lots of tenders - a perpetual license is usually two years of the subscription fee plus 20% of the perpetual license cost as support fees).