Depends on the seam. I don't pin when I sew strips. I always pin when I want my seams to line up. I've heard people say that "if you cut and piece accurately, you don't have to pin. So many factors weigh into that, though....fabric can shift, even for the best of us. When in doubt, pin.

Thank you all for your opinions. I usually pin (and baste) where intersections are and for longer seams, but I skip this step for shorter seams. Right now I'm sewing 2 3" squares together. Whereas before I would just stitch these together, this time I've decided to take the extra time to pin. Hopefully this will work to make things a little less wonky for me. If I were to sew two long strips together of the exact same length without pins, by the end of the strip I would have an overhang of a half inch or so on one strip. I'm not sure if it's just my sewing machine that does this or if they all do, or if it's something I'm doing to make it happen. So for the long ones I definitely need to pin.

If I am sewing something where the edges don't line up - like a triangle in a square unit , or a half-rectangle unit - I match the intersecting points, and then pin.

A "regular" presser foot - as compared to a "walking foot" - usually feeds the bottom layer "faster" than the top layer.

Which is why if something needs to be eased in - the longer length is "down" and the shorter length is on top.

Something that has kind of helped me - when sewing long strips together - I hold the pieces so that they are about four to six inches above the machine bed.

My theory is - the lower/bottom piece now has to travel a teeny bit further than the top piece - so sometimes that seems to help make the pieces "come out even".

Fabric has tensions of it's own in it, and then the seam has tension, and small amounts of tug or pull that we put in all contribute. And I say that some fabric is treacherous! It wants to move and shift and cause issues, even if it is all high quality cotton.

I prefer the modern strip piecing methods and trim things down to fit. Whenever I can when I'm putting two sets of fabrics together, I sew first, cut second. If everything is scrap, that can be hard to do. But my preferred solution would be to use one long strip of "background" and then my individually carefully cut squares on top of that with maybe 1/2" between them to deal with those twists and strains.

On a recent project I was taking process photos, this isn't the best but it shows the general idea. With these fabrics some were very large scale prints and I deliberately oversized the pieces a bit so I could at least be slightly fussy with the cuts.

Edit: To clarify, those pieces that are on the dark green were further subcut into (two) 2-square units. As was the blue/brown piece. Originally when I used the green strip I would have had additional other 2-square units (maybe 6?) along the length but I cut the others off.

And this is what it looked like finished. Sort of hard to envision from this picture here!
https://www.quiltingboard.com/quilti...ml#post8284787

I rarely pin - if there are sections to match I will beat the seams as I go and sew more slowly as I find this more accurate. Borders or long strips I do match up key points before I sew but tend to use clips more than pins.

I use pins more in bag making when I want to keep several layers together

I’m a die hard pinner and starcher, these 2 things help me do my very best work. Does it take more effort? Yes, but for myself it’s what I like and it’s what works for me.

I'm the same way. But I normally do not pin binding, haha, except at the mitered corners and I pin the heck out of those!

I'm very on and off about pinning. Sometimes I do and sometimes I don't. I usually pin borders but I don't pin intersections. I use a drop of Elmer's glue on intersections. I rarely have an intersection that doesn't meet since I've been using Elmer's.

I always pin borders and carefully make sure the edges are even. I always pin intersections, I love for them to match perfectly.