I always put mine down but never was told to put fabric under. I guess it goes back to when there were little ones around and I thought it would be safer to put the foot down. That was many moons ago but I just got into the habit.

I find that leaving the foot down with fabric under it, I start my next seam like I'm chain stitching and I avoid the bunching up that can sometimes happen when starting sewing. I'm currently using my headers and Enders to put together a scrappy quilt while at the same time sewing a "regular" quilt.

The purpose of the fabric is to use it as a leader for the next bit of sewing (If you're not changing threads, of course. lol)

I didn't read all the replies, but I use to work in sewing factories. We always cleaned our machines at the end of the day and put fabric under the pressure foot. The fabric under the foot was to catch any oil drip so at the start of the next day when starting to sew, there would be no oil on the product.

For my home machines I don't put fabric under the foot, but I do put the foot down. I don't believe it is good for the spring to leave it up.

My embroidery / sewing machine, has a special button that locks all buttons and puts foot down for storage, transporting, etc.

It's not about your upper thread tension assembly....It's about tension on the spring for your presser foot bar. When the foot's up, the spring is compressed.

As I read through this thread, I was wondering about this too. Leaving the foot down is not anything I was ever told to do or have ever really thought about and I've been sewing for more years than I want to admit. But I guess I do usually leave the foot down. But I ALWAYS leave the needle up after a close call I once had. The fabric in the machine caught on my clothing as I stood up and it yanked the needle and bent it. It was lucky I didn't bend something on the machine out of whack. On my electronic machine, the needle position is reset every time it powers up, so I leave the needle up so it won't put undue stress on the needle or the machine.

I was told many years ago in Home Ec class to put the foot down with fabric under it to catch any oil that might drip down. The purpose of the needle down at that time was for safety. There were small children around in the homes most of the time. Now days I don't leave the pressure foot down unless I am transporting my machine. The reason for this is also a safety issue. My machine won't work if the foot isn't down. So with the foot up if one of my grandchildren happens to try playing with my machine it won't sew their fingers. Also the fabric under the needle on older machines was because it could do damage to the machine if sewing was done without fabric in it. I have been told the newer machines aren't like that.

My DH says the fabric keeps dust and lint from the air getting into the feed dogs and with the foot down it does take the extra tension off the machine. Hope that helps!

I leave mine in the down position. Leave a piece of fabric in it. I to have been told this by service repair man.