Vet or no Vet?

One of my mice has a probable tumour and it raises old issues again; should I take her to the vet, and when? There are pitifully few treatments for mice in England. The vet will likely just want to put her to sleep. This is a 99 percent sure fact. But she doesn't seem ill enough for that yet. Do I take her twice, pay twice, stress her twice? Do I hold out on the 1 percent chance they can do something? Or do I leave her to nature and only take her if she seems to suffer, and live with the uncertainty? Pet keeping, so much responsibility. Also, I'm having trouble finding company for her single remaining cagemate. Alone she could go a bit mad (seen it, its not nice) or even pine to death... But my normal store has no new bubs in. Sigh.

On a non rodent note, work is slow and nothing to report.