No university degree, did an apprenticeship 14 years ago in germany. It was three days a week of learning sysadmin things within a company (Windows, Linux, network devices) and two days a week of school, where the theoretical stuff was taught.
After 3 years, I was a newbie sysadmin and capable of managing Windows and Linux environments. I did no further certifications back then.
Over time, especially since I wanted to move more towards Linux, automation, containers and cloud native things from 2022 on, I did some certifications (LFCS, RHCSA, RHCE) which helped me to land a job where I now work 100% with Linux and containers and kubernetes.
I did it to:
learn the things I had experience on from the ground up and fix the all the “holes” I never had to work with before in the day to day job and get a verification of my skills.
learn additional things that were not part of the apprenticeship but are useful as a sysadmin today (automation, containers, git, etc)
I’m still learning to build up knowledge of kubernetes and will eventually take exams on that topic as well.
However, there are certifications with questionable value to them (in my opinion), like multiple choice tests for single tools or the like.
I’m a fan of performance based lab exams, where you get 20 tasks from all the scopes of the product to solve and have to actually apply the knowledge you gained to pass the exam by solving real world problems.
By learning for those kinds of exams, you cover a product or technology - almost - 100%. Unlike learning by experience only, which can be very individual. You can for example totally manage 10 linux hosts with ansible for 10 years without ever having to use facts, roles, etc. Just by writing very big playbooks.
Does that qualify for 10 years of ansible experience?
In reality, companies have a certain size and use-cases, so you’ll do the absolute minimum to get something running/implemented securely (most of the time, I know there are exceptions). So imho certifications provide a birds eye view and force you to learn different areas of the product, which may be very useful, out of scope, etc.
But just passing a certification exam once doesn’t equal years of real experience either. It’s a mixed topic. For a point in time, you knew enough to pass the exam, so if your certification is still valid, it would be reasonable to assume you still know what you’re doing, that’s all.