The mechanics of how the items gain experience and what that experience provides will have a big effect on how they affect economics and production. I'll walk through an example to show some of the ways you can determine how the particular mechanics you choose will affect things.
RPG character style experience
Suppose they gain experience as if they were RPG characters - no matter what they are used to do, they'll gain some experience. Higher levels of experience give the person using the item a better chance of doing what they were trying to do and with a higher level of quality, and the item itself will become more durable. Repairing a higher-level item to perfect condition is as easy as repairing one of lower level to perfect condition.
This probably requires a magical explanation for how they gain experience, such as being crafted by wizards. That implies that only skilled crafters can make such items, so they would be more rare and valuable right off the bat. Repairs would have to be done by someone of similar (though perhaps distinct) skill, so repairing would also be expensive.
Because in this scenario only the experience matters and not how they obtained that experience, items will be priced based mostly on their experience, with the current condition of the item only playing a secondary role. Since repairing a low-level item is expensive, most people would opt for normal, non-magical items - at low levels the non-magical items are almost as good, and you can get many of them for the price of a single magical one. Anyone buying a low-level magical item would expect to end up putting quite a lot of time and money into making the item better.
There would be quite the market for high-level items. Due to the significant investment required to get them to that level they would be very expensive, but as you would be able to get significantly better products using the items the elite would get them whenever possible. This would also result in the elite owning the tools that the craftsmen doing jobs for them would use.
There would also be a market for mid-level items. These items could come from the people who repair items for a living - they would buy low-level items for practice, whether for themselves or for training apprentices. This way it's less of a loss if the repair goes wrong and the item breaks permanently. Then after a while of using it and repairing it, the items will be valuable enough that they will want to sell it.
This also encourages the development of agreements between different tradesmen - for example, with cooking pots they'd make an arrangement with the local restaurant to have them use it for their trainees to practice on so that it could get experience between repairs. When it comes time to sell the item they would share the profit, either by the repair shop selling the item or the restaurant keeping it to begin using for food that they'll actually sell.
Other than that, there wouldn't be many ways that low-leveled items would be used enough to get more experience. You'd get the occasional person from the upper class who wants an item and can't find one that's a higher level, but other than that the cost of getting them to higher levels would be prohibitive. This lack of demand for low-level items would lead to fewer creators being interested in creating them, further increasing their rarity.
All in all, this leads to a fairly small impact on the normal economy. Thanks to their scarcity and cost, you could think of it being similar to expensive art in our world. The upper class would buy as many magical items as they can, but they would be prohibitively expensive for the lower class. The middle class might be able to afford one or two mid-level items. Restaurants and other businesses would be similar - the expensive, fancy restaurants would exclusively use magical items, nice but reasonably priced places would have some mid-leveled magical items (thanks to their arrangement with the repair shops), and cheaper places would not have any.
Small changes to these parameters could have huge changes. For example, if repairs were easy to make then there would be more demand for low-level items, leading to them being even more expensive to buy. It would be much more viable for people to make a profession out of leveling up items and then reselling them - there is the significant initial cost, but after that it's mostly time that they have to spend. With people willing to buy them, more creators would be interested in making the items, leading them to be more common. With them being more common, more of the economy will revolve around acquiring and using them. You wouldn't find magical scissors in my original scenario (not much use for how expensive they would be), but in this scenario they might show up.