When I have a piece that long, it generally means that part of it is backing. I measure that piece generously and rip it - then can generally deal with the rest of it without too much of a problem.

I never cut up long yardages until I am ready to use in a project. Then plan for what I want to do and then know if I can cut one yard chunks at a time. For cutting I can then do 1 yard at a time so that it stays straight. I do not take a real long time to fold that long yardage precisely selvage to selvage when I am just putting it away. Life is too short - I get it sorta there and put it away. When its time to use it then its time to fuss with it.

Hope you all read between the lines. LOL After I place my hands side-goggling I stretch the fabric and then stretch the other way. So much for leaving out inportant info! Duh to me!

if you are cutting from large pieces, you need to realign every half or so yards. One well known quilter/writer suggests checking about every 6" of cut to make sure the ruler hasn't slipped. I have a "big board" and I alighn the ends and lay the piece over the board and then iron. As I go along I check to make sure the fabric has remained straight. this usually works.

I try to square up the selvage with the edge of the fabric, making sure the beginning fabric cut line is straight. Then if I am careful, the cut lines are going to be straight. Good luck

I don't cut my fabric, even the longer pieces. I'm afraid of how much I would waste if I cut it up. I hang the fabric pieces over the staircase and get the edges to line up. I prefer 3 yards or less, but the longer is doable. It's folded in half lengthwise and I've learned to adjust it so that the edges are even. I give it a sharp snap (like when you are folding sheets). I fold it by wrapping it around my 24" ruler, then slide the ruler out and fold the fabric roll in half. It stacks up quite nicely that way.

I was taught to straighten the grain of fabric by pulling the bias of the fabric until the selvages are parallel. When the yardage is very long this is rather daunting to do. However, if you find a "helper" it is very doable. Find the true bias and have you and your helper move down the length of the fabric (pulling in the bias dimension) at the same intervals-maybe 6 inches at a time. Check frequently to be sure you are maintaining the straight grain. I like to do it this way so I can make borders on the lengthwise grain whenever possible. Keep the options open by keeping fabric in one piece. I might add that I like to cut lots of pieces lengthwise rather that crosswise because it is more stable.

If I need to keep it straight, I will cut in about 1 inch and rip it, then trim the ratty edge. It works for me.

I know if I cut the yardage it would wind up in the wrong spot and I'd be short of fabric! LOL

When I fold long yardage I start in the center (3 yds in your case) and line it up there. Then I work toward each end. While not perfect every time, it's better than cutting in the wrong place. Fabric can always be ironed again when I know exactly where to cut.

I would assume this is for when you are ready to use it, not for storage. I wouldn't think cutting fabric into "manageable pieces" is a good idea if don't know what you are going to do with it yet.