You received a repair quote. It is higher than you expected — close to what you paid for the piece, or close to what a replacement would cost. You are stuck between two numbers that are too similar to make the decision obvious. You need a framework beyond just comparing dollar amounts.
If repair costs more than replacement, replace it. That is just basic economics.
"If you replace this piece, will you actually feel like you have the same piece — or will you always know it is not the original?"
Ask the jeweler: after this repair, what is the expected remaining life of the piece — specifically, what is likely to fail next and approximately when? If the answer is several years, the repair may be worth the cost even if it approaches replacement value. If the answer is months, you are buying time, not a solution.
There is no fixed threshold. Consider: repair cost vs replacement cost, expected remaining life after repair, whether the piece carries meaning a replacement cannot replicate, and whether the repair is a one-time fix or the beginning of repeated repairs. A three hundred dollar repair on a five hundred dollar piece may be worth it if the piece will last years afterward. The same repair on a piece needing another repair next year may not be.
Repair is usually cheaper than replacement for common fixes — ring sizing, prong retipping, chain soldering. Replacement becomes competitive when the piece needs extensive work — full shank replacement, multiple stone resettings, or restoration after significant damage. Get a repair quote and a realistic replacement estimate before deciding.
Most jewelry insurance policies give you the choice — within the policy limits. If a piece is damaged, the insurer may offer repair cost or replacement value. You can often choose replacement even if repair is possible — check your policy. The insurer may require you to use their approved jeweler for replacement.
Professional repair maintains or restores value. Poor repair reduces it. A well-executed prong retipping or shank replacement is invisible and preserves value. Over-polishing, visible solder seams, or poorly matched replacement stones reduce value. The quality of the repair matters more than the fact of the repair.