What’s going on with mine?

I’ve had this plant I think around 3 years now and the leaves have never looked as bad as they do recently. The last 2 years I had it by a north facing window so it didn’t really get TOO much light, but around 6 months or so ago I moved it by a west facing window so it’s been getting more light in the afternoon/evening.

It’s still sprouting new leaves on occasion, but all the older leaves below them have started developing these brown spots and some leaves have withered and fallen off.

Is this not enough watering? Too much? Too much sun?