Getting More Robe of Useful Items Patches

[WhiteWolf]

Hey, so I was wondering what would be a good way for players to get more patches for a robe of useful items.
I initially thought just have them buy more from magic item shops but then I thought about having a spell that would let them make them. So I thought about it and came up with something but I wasn't sure how it balanced with other spells so I wondered if anyone could tell me if 3rd level is about right or if it should be higher. Thanks

On the Bard, Sorcerer and Wizard spell lists.

Create Useful Patch
3rd level Conjuration (ritual)

Casting Time: 10 minutes
Range: Touch
Components: V, S, M (a blank patch made of fine cloth and thread worth at least 5gp and the item or items you wish to make into a patch)
Duration: Instantaneous

You compress a useful item onto a blank patch to create a new patch for a Robe of Useful Items. The item or items you choose must be no larger than 30 foot in any dimension. If any of the items chosen is a living creature, they may not have a combined challenge rating of higher than 1/4. The patch must then be sewn onto a Robe of Useful Items before it can be used.

[Ventruenox]

This looks fantastic. It keeps the Robe of Useful Items from being too disposable, and items that would likely be used could be replenished. The only balance issue I see is there would need to be a cap to the number of patches the Robe can carry at any given time. I may have to make a demented Girl Scout character just to utilize this spell.

[Aett_Thorn]

And maybe have a maximum amount of patches that could be added over the lifetime of a given robe? It can still be fairly high, but otherwise they'll just rip everything off during the adventure, and replace once they get back. Maybe like 3d20 of replacements before the base robe is in too bad of a shape to add more?

[WhiteWolf]

Yeah, I agree that a maximum number of patches would be a good idea. The most patches you can get on a Robe of Useful Items is 28 so perhaps that should be the limit you can go up to.