I don't see why you'd want to toss any drawings. They're a record of where you've been and where you're going and they can give you valuable insight into what you do well and can expand upon and what you need work on. One day it might be nice to look at them and get some perspective on how far you've come. I keep my basic warmup line and circle exercises in a separate sketchbook and I don't mind tossing in those although even then it might be nice to see how much you've improve at those over time. If you're working digitally you have the benefit of not needed to worry about sketchbooks taking up physical space even if the trouble of choosing how to organize comes into play.

I struggled with the shading but it’ll get better With practice. This is my 3rd study and it came out the best. I tend to over elongate the eye so I drew more guide lines to help with proportions. Feedback appreciated especially on proportions!

I was a little nervous taking this study on, but I like how it came out! I need work on perspective for the back half of the avocado, but I’m happy with how this came out. Feedback welcomed.

Here’s my pear. This is my second attempt.

This model really helps understanding the head in different views. Here's my attempt.

Omg this is so helpful when I can't quite grasp the curve around the front plane when practicing my heads.

Egg practice Though I am drawing digitally, I work hard to restrict my options so that I don't hurt my learning progression. I disabled my undo shortcut, use a simple brush tool (pencil), and I try not to change the zoom level while drawing. I am not sure if these limitations are enough to overcome the benefits of using pencil and paper to improve drawing skills. I hope so. I suppose I can compare an egg drawing I do on paper with this digital drawing, though I am not sure that is a valid skill test. Any thoughts?