In my experience, SSO is a requirement for some corporate clients. So depends on who you are selling to (individual employees or orgs who will have a number of their employees use the software). For example, if you sell a quoting tool to a department, which will then be used by their salespeople, SSO requirement is a possibility. If it's a small app that the CEO will use to schedule posts on Linkedin, then there is no need.

In my experience, login using Google, Apple is a convenience feature that may increase conversion rate if the product is sold to individuals, but is not essential.

Your experience may vary.

SSO has various levels. You can do a "Login/Signup with Google" using any of the popular frameworks in a day or so. On the other hand, if you need to do full Enterprise level SSO (SAML, Audits, SCIM etc etc), you have more work to do.

Look at it this way. If your product solves a real problem for your potential customer, they wouldn't care about how to signup for it. Not until they tell you that SSO is a must. Until then, don't sweat it and keep going.

This is exactly what we built WorkOS for.[0]. I’m the founder and we launched on HN a few years ago.[1]

Our auth service is free up to 1,000,000 users. We charge for enterprise features. Send me a note if you’d like to chat![2]

[0] https://workos.com/user-management

[1] https://news.ycombinator.com/item?id=22607402

[2] mg@workos.com or https://x.com/grinich

Your potential customers are the ones to ask. The opinions here will be varied, and unhelpful.

Unless your target market is HN folks. If it is, you're absolutely in the right place and ignore everything I said.