It really depends on the type of service, but I think the healthiest approach is to build recurring revenue rather than relying on one-time sales.
For hosting providers, the obvious foundation is recurring hosting fees, but there are plenty of complementary services that add value for customers, such as managed services, backups, security, monitoring, control panel licenses, domain registration, SSL certificates, and premium support. Custom infrastructure, migrations, and consulting can also generate revenue while solving real customer problems.
The key, in my opinion, is that every paid service should have a clear benefit. Customers are generally willing to pay more when it saves them time, reduces risk, or improves reliability. Long-term retention is usually more valuable than maximizing revenue on the initial sale.
I'm curious how others approach it. Do you focus primarily on recurring subscriptions, or have add-on services become a significant part of your business?