How do you decide when it’s time to have your pet put to sleep?

Let me start by saying I’m not talking about Spooky…she’s fine…mean as ever…


I’m talking about Goldi…poor old Goldi…she showed up a few years back…cold and hungry.  I really didn’t want another cat, but I felt sorry for her.  So I fed her and gave her some water on the back patio, hoping she’d find her way back home. 
Who knows what her story is?  Was she abandoned?  Did she escape and couldn’t find her way back home?  I have no idea.  She is so friendly that it’s obvious she was once someone’s pet.  This is why I preach to people to keep their cats inside…bad things happen to them on the outside…
Goldi was probably luckier than most stray cats.  I never found out where her people were, but I did take her to the vet and had her checked out.  Other than being old and skinny, there wasn’t anything wrong with her.  So I let her explore the house and try to get used to Spooky.  Funny, Spooky wanted to be friends right away, but Goldi never warmed up to her.  Maybe because she was so old and didn’t want to play…So they never really became friends, but they tolerated one another.
A few days ago, I noticed Goldi was becoming lethargic…still eating well, drinking enough…but just not getting around like she had before.  Last night, she just kind of stayed on a chair in the spare bedroom, didn’t come downstairs to eat.  When I took food up to her, she ate it, but I could tell something was wrong.
I took her to the vet this morning.  She wasn’t happy about that.  (Is there a cat in the world who enjoys going to the vet?)  They examined her, took some blood, all of those good things.  As far as they could tell, without further tests, she’s just getting really old.
I kind of feel guilty for not okaying more extensive tests, but it’s not something I feel like I can afford…then I question myself, if it were Spooky in this situation, would I go ahead and pay for the other tests?  I have to admit, I would be inclined to.  Does that make me uncaring for not doing it for Goldi?  The vet and I discussed putting her to sleep.  She said she didn’t think Goldi was in pain, but that it’s not always easy to tell with cats.
I brought her back home and have made her as comfortable as I can upstairs in the spare room where she can be warm and keep away from Spook.  She’s still eating and drinking.  I go in and pet her and talk to her several times a day.  But I don’t know…should I think more seriously about having her put to sleep?  How do you know when it’s time?  She doesn’t seem to be in pain, but she’s also not really doing much…I know it’s only a matter of time now.
Would it be better for her to just go ahead and schedule it sooner rather than later?  I just feel so bad for her.  What have you done in these types of situations?

Spooky and Goldi