One of those things.. you think "eh, I don't need it!" and go on your merry way for years. Then something happens, you come across a video of someone using it, a friend, or a post on GJ. Then you realize what you spent years missing out on. How many countless hours were wasted for results that were less than satisfying And realize that the tool in question would have given amazing results in seconds instead of hours.
That's when you kick yourself in the ***. A belt sander is one of those tools. Even a cheapie meant for wood instead of metal can give amazing results if you treat it right and have time. But, for beveling, squaring ends of stock, and countless other things it's hard to beat one.
Here's a prime example: You're building 1 or 2 small frames out of square stock, nothing big just 2"x2" 1/8" wall tubing, **** welded to each other at 90 degree angles.
You load your metal up in your chop saw, fence set to "eh, that looks like 90!" and cut away. You start fitting up the pieces and realize that if you square them one corner has a 1/8 or 3/16" gap. Have to play the rotate the piece and find one that fits game, or just whip out the grinder and get it close, damn went too far, now it has a gap in the opposite direction and will be too short if I grind the other side! game.
Enter Belt Sander/disc sander: Set fence up for 90 degrees, double check with square or what have you. Put stock against fence and a few seconds later perfect 90 degree angle with smooth burr free edges. Oh, you need to bevel the ends for welding? Set the fence for 45 or 60 degrees, slide the metal against it and presto! perfect bevel on each piece in seconds.
Same for dressing up welds that need to be flush and countless other things including tons of knife work!