Tenant wants oven replaced, it's not broken

[Sam T.]

I'm a new landlord and not quite sure what to do in this situation, so any advice is greatly appreciated. My tenant asked me today if I would replace the oven (gas stovetop) because it has a lot of tiny grease stains all over. It's overall a little worn out and has stains here and there but it's still perfectly functional. Aside from being nitpicky with this type of thing, she's a very solid, clean tenant. What would you all do here? I'd hate to replace an appliance that works just fine but I'm not sure if it'll be possible to get all the grease stains off. The oven is 9-10 years old by the way.