How often are you suppose to change the needle in your machine?
2. If u have older singers are u still suppose to take them in once a year? How do u afford it when u have multiple machines??

How old are you talking about? My old machines are 75-100 years old. They are easy to maintain--no need to take them anywhere--just keep all the gears oiled up and the bobbin area clean.

Wish I could answer this for you but I'm really bad about changing my needles and neither of my machines have been professionally serviced. I just can't afford it so I try to keep them cleaned and oiled.

Old machines are easily cleaned by their owners. That's part of their beauty. I change my needle every time I start a new project.

I change my needles when I hear them make a popping sound, or my stitches aren't right LOL OR on the rare occasion that I remember it has been a while :oops:

I clean my own machines, and do not take them in unless they need a repair that I cannot do :D:D:D

My machine has not been serviced by a pro. I just clean and oil and if anything needs to be fixed I either get a repair book or find a tutorial on the net. I like to do everything myself if I can.

My husband bought me a Viking for Christmas about 5 years ago. I set it up so I could use a cone of thread (with the thread coming from the back side of the machine) and, yes, even though I took precautions the thread coming from behind wound a hundred times around the hand wheel. I almost cried because our Viking dealer had just closed its doors and all I could see was big $$$ signs in front of my eyes if I took it to a repair shop. I worked for hours trying to manually unwind the thread. Oh, did I mention it was Sulky Rayon thread, Ugh! I finally gave up. When my husband got up that morning I confessed and showed him the machine. He got the plastic wheel off and I was able to remove a lot of the thread but it had gotten down inside the plastic case around the arm that holds the wheel on. I sat there and checked all the places where it appeared the case separated and found another screw to remove and, walla, the case came off and I was able to remove every bit of thread. I gave the machine a good cleaning inside (surprisingly very little thread or lint accumulation) put that baby back together and she purrs like a kitten! Of course, I would never have attempted this if the machine was still under warranty. Even the newer machines can be maintained (to some degree)at home.

needles should be changed between each project or after 8 hours of sewing time--which ever comes first- and sooner if you start having uneven or skipped stitches- some fabrics will dull the needle faster than others.

you should clean your machine every second bobbin---and if it's a new-fancy machine---follow the maintenance guidelines in your manual--they tell you how to clean it and oil-if it needs to be oiled-
if you start having problems with stitch quality or other issues it may have to go to a shop-but you should be able to do 98% of the maintenance yourself for years. i do have a computerized machine- which i've been taking care of for a long time- it's been in to a shop once in the past 5 years--had a problem with my reverse ... but that was a whole different matter :)

You can take care of an older mechanical machine yourself.
A newer electronic/computerized one needs a bit more than the average sewer can do. In part it depends on how much you use it. If you only sew once in a while you can stretch out the time between shop visits.