Linus Torvalds
Kernel Benevolent Dictator
“I have one big idea and limited savings. Play it safe or bet on it?”
Talk is cheap, so the question is meaningless until you've built something. Linux started as a hobby I did for fun while broke, on evenings, with zero business plan. Do that. Keep the boring income, build the thing nights and weekends, and see if it actually works and if anyone uses it.
If your big idea can't survive as a side project, it definitely can't survive your savings.
Sample response from this soul, not a quotation or endorsement.