The slog is over! Congrats on getting 250 boxes drawn; that couldn't have been something done in a day!

Most of these boxes seem to be drawn very clearly in third-point perspective, so great job there. There's also only a few incorrect contour lines, so you seem to firmly grasp the concepts of vanishing points.

Something that I think you should be more wary of though is the practice of redrawing lines on your boxes. I know how it feels when you make a mark and you immediately know it's not right; I've done it plenty of times on my own 250 Box Challenge and I too have immediately made a new, more correct mark in its place. This is a noticeable thing in your submission, though, as practically every page has crossed-out and redrawn lines. I even noticed a completely crossed-out box around the 150 mark (that poor thing!).

This issue is likely just an issue with confidence in your lines. Either that, or it has to do with not having enough patience when making marks. Don't be afraid to slow down a bit and visualize where your mark should go. And even if you make a mistake, try not to get upset and redraw the mark; yes, it's incorrect, but as ol' Bob Ross used to say, "we don't make mistakes, just happy little accidents."