Question for those with bird feeders

I use thirty pounds in thirty days. I buy it in forty pound sacs, sometimes I have to buy two at a time to keep it at about fifty cents a pound.
I feed squirrels, too, and they need that.
I go each day, and feed at three spots very close to each other.
There are natural bird feeders - a fence, a rock, two different trees, the ground- I put lots of little piles so they don't get in each others way). I also distribute cubed peanut butter sandwiches and a few roasted peanuts.
This is always eaten up, maybe a little millet from the birdseed will be left behind.
(Stream areas and a hedgerow also take occasional deer corn or sliced carrots and apples, and leftover but not too stale cakes and sweets for nightime critters)

I dunno, I've seen squirrels get into every 'squirrel proof' thing there is.
it kinda depends on what sort of thing you're using as feed and how many birds you get.
15 is a tad high, how often do you refill it?

Unless you're in a cold climate with snow and ice on the ground probably best not to feed too much this time of year.

Animals tend to keep populations of pests under control if they have to find their own food and birds are an important part of the ecosystem.

Do a bit of research specific to where you are.

Those birds expect too much from us 😝