#1 维修费用如果大于50%新的价格，就应该更换
that’s a widely used guideline, often called the “50% Rule” in home maintenance.
The logic:
If the cost to repair an item is more than half the cost of replacing it new, it’s usually better financially (and often functionally) to replace.
This also assumes the item is past the halfway point of its expected lifespan.
Why it works:
Better value long-term – Repairs on older items often lead to more repairs soon after.
Efficiency gains – Newer models are usually more energy- or water-efficient, lowering utility costs.
Warranty advantage – Replacement restarts your warranty period; repairs usually don’t.
Example applications:
Appliances – Fridge, washer, dryer, dishwasher.
Fixtures – Toilets, faucets, garbage disposals.
Tools – Power tools, vacuums, lawn mowers.
Exceptions:
Items with high sentimental value (e.g., antique furniture).
Rare or high-end products where new replacements are much more expensive than repair.
Situations where the repair is a one-time fix that restores full function for years.
For most household goods, you can combine the 50% cost rule with a 50% lifespan rule — if it’s more than halfway through its expected lifespan and the repair costs over half of new, replacement is the smart move.
When 30% makes sense:
The item is already past 70% of its expected lifespan.
The model is outdated and inefficient.
Parts are hard to find or expensive.
You value newer features or design upgrade