1970 c10 stock rear coils

[NathanJ72]

I have a 1970 c10 that I have to replace the control arms on as one is rusted through. I don't have a ton of money or I would replace everything (may have to anyway) and I am torn about replacing the rear springs. Do the coils actually wear out? She doesn't seem saggy at all and pardon my ignorance on the subject. What say you all? I have included some pictures to show she doesn't appear to be sagging, and I do NOT want to lower her.