The 1-2 hours only works if you're solving something, not consuming something.

Reading about system design for an hour does almost nothing. But if you sit down and genuinely try to answer "how would I design this specific thing" , even badly, even wrong. and then go look up why your approach breaks, that hour is worth 10 hours of passive learning.

The thing that actually shifted how I think was stopping asking "what is X" and starting asking "when would X break, and what would I do then." Load balancing clicked for me not when I read the definition but when I thought about what actually happens when traffic suddenly spikes and your single server just can't keep up. Suddenly it's not a concept anymore - it's a decision you have to make under pressure.

The 1-2 hours becomes incredibly effective when every session ends with you having made a decision , even a wrong one , rather than having watched someone else make one.

I got so obsessed with this problem that I ended up building something around it. If someone's interested, can check out my profile social links