Modifications and upgrades: do they really add value?

Spending €300 on pickups, tuners or components does not mean the instrument is automatically worth €300 more.

An upgrade may be valued when it is reversible, professionally executed, documented and desirable to a broad range of buyers. It can reduce value when it permanently alters the item, reflects a very personal preference or removes original parts that are difficult to replace.

Compare the original model with genuinely similar modified examples. If the original parts are included, say so: reversibility often reduces the negative impact.

Upgrade value and upgrade cost are different things. The market pays for what buyers want, not necessarily for what the owner spent.