✔ 最佳答案
A general rule of thumb for consumer products is that if the repair will cost more than 50% of the value of the item, you should discard it and get a new one.
Note that this applies to "consumer products" and the "value of the [actual] item" if it were in proper working order. If the value of a replacement item is exorbitantly high, this rule may not apply; and of course it doesn't apply for items of collectible or sentimental value.