Asking for a Friend? How long does it take to transition from SDR to CSM?

How long do you need to be an SDR before you can transition into Customer Success? A few days ago, I spoke with a friend who had 1+ year of work as an SDR at a SaaS company. Unfortunately, they got laid off and didn't believe their dreams of becoming Customer Success Managers would happen. I tried to reassure them they could still convert because they have tons of SaaS experience, but they weren't convinced. To me, having SaaS experience gives you some advantages compared to candidates that don't have any SaaS experience.

How long do you have to be an SDR to change careers within tech, precisely Customer Success? 

Does the recession make it harder for folks to transition from SDR to Customer Success?

Please share your thoughts below. I'm curious about what folks have found.