This is quite a long post but title says it all really - how do you know when the right time to put your ill rat to sleep is? And do you have any tips for getting through it?
I’m unfortunately in a situation where I’m having to think about this now and I’m finding it really difficult

One of my rats has had a lump growing under her arm for a month or two. She’s quite an old girl at over 2 and a half years old (she will be 3 at the end of February), so I made the decision that I wasn’t going to get the lump treated as I didn’t want to put her through an operation which won’t prolong her life by very long anyway. I’m sorry if you disagree with this, I just personally didn’t feel that it was the best thing to do for her considering the circumstances.
One thing that I did promise was that I wouldn’t let her suffer on for too long with it. I knew I would find it hard to make the decision when the time came, so I made some ‘guidelines’ for myself while I was in a clear frame of mind about when would be the right time. I can up with things like ‘when she is showing signs of pain’ ‘when she isn’t living her life to the full any more’ ‘when her mobility start to suffer’ and things like that.
I think I’m getting to this point now unfortunately. The lump is getting very large and she’s not getting around as easily as she used to and is getting quite thin. She’s having trouble getting in and out of the narrow door of her bed. However she is still enjoying her food, cleaning herself well (except for some bits that she can’t get to with the lump being in the way which her sisters help with), still plays with her sisters the same as always and seems to be in otherwise good spirits.
In one respect, I think it’s time to book her in with the vets as it’s getting so big that she’s having trouble getting around as well as she used to, and I know she’s not really showing it but I assume that it must be uncomfortable for her too. The fact that she otherwise has quite a good quality of life is messing with my head a bit - I don’t want to cut her life unnecessarily short. I really don’t know what to do.
I’d really appreciate some opinions of when other people think it’s the right time.
Also, if you’ve got any advice for me really on how to make it sort of ‘emotionally easier’ for myself I’d appreciate that too. I’m obviously upset but I think this is making it play on my mind and making it difficult for me being logical about it.
Thanks