I have said before that I have a problem letting things go. I grew up and have lived by the rule that if something still has some use in it, you use it!!! I use my bath and body products to the last drop. I wear clothes until they're worn then they get moved to the "house and yardwork" clothes then ultimately to the rag bag. If something is not broken beyond repair --- I keep it and use it. I also would also only change my sewing machine needle when I broke it and I used rotary cutter blades until they began to chew on the fabric.
I am changing my practice!!! I have been experimenting with changing my needles often and have had very good results. The benefits and ease of working with a new, sharp needle far outweighs the expense. My stitches are smoother. My work faster. The fabric less stressed. I had not realized how long I was using needles because I seldom break them. Sharp and new is certainly the way to go.
I have also found that using a new rotary blade is a faster and safer way to cut. I do have a system for retiring my old rotary blades. I use a new blade at the start of a big project. I mark the start date on the blade with a Sharpie Marker so I don't loose track of how long I've been using a blade. The "old" blade is then moved to a rotary cutter I use to cut materials for crafts (ie felt, vinyl etc). The "craft" blade is then moved to a third rotary cutter that is used for everything from paper and light cardbord to plastic. After that, the blade has finally served its purpose and is wrapped in duct tape and disposed of safely.
Next time you are out shopping, treat yourself to some new needles (hand and sewing maching) and a new rotary blade or two. You will be amazed at the difference these new, sharp tools make. Happy cutting!