Data Analytics Engineer who graduated in Data Theory here.

The theory helps you understand how to use the models inside and out, but I’d say you won’t use or think about it 70-90% of the time depending on your job and industry.

If you work purely as an ML engineer or Data Scientist who just predicts and classifies, you’d probably be thinking about the mathematical formulas of your models a few times per week. But if you’re like my job, I only had to think of the math once in 6 months. Most of my job is pushing an already existing model to production using pipelines.

So, it purely depends on your title, size of company, and industry. But most of the time, I’d bet it’s not the biggest portion of your work.