What is the usage period for the eye drops prescribed by the ophthalmologist...?

I received an eye examination at the ophthalmology clinic and got two types of eye drops.

I was told to come in three days, but since my symptoms haven't changed, I haven't gone and am just using eye drops...

It's been about a week, is it okay to use it longer?

I think they said to open the eye drops and discard them after about a month...

If that's the case, I think it would be better to lower the amount and give less...ㅡㅡ: I feel like I always leave more than half behind and waste it..