The real question isn't whether you'll save money, but whether you can afford to lose it if something changes. A 20-30% discount sounds great until you're stuck paying full price for a different hotel because your plans shifted, or worse, you eat the entire cost and don't go. That's when the "savings" vanish fast. Non-refundable rates make sense only if you genuinely have zero flexibility and could live with losing that money without it stinging.
Since you're already second-guessing yourself ("something could come up"), that's your answer right there. Your gut is telling you there's uncertainty, so listen to it. Spring is several months away, and a lot can happen - illness, family stuff, work changes, financial surprises. Most people who regret non-refundable bookings had the same nagging feeling beforehand that you're having now.
That said, if your dates are locked in by external factors (conference you're attending, someone else's wedding, school holidays that don't budge), then the cheaper rate might be worth it. But if this is discretionary travel, the peace of mind from keeping your options open is often worth more than that discount. You could also split the difference: look for hotels with a refundable rate that's only 10-15% more expensive than the non-refundable option. That's usually a better compromise than the full spread you're seeing.