Think about your budget when you start doing your research to buy a sewing machine. There are times it's fine to be slightly flexible, though, do not go over your budget range by much. You may not have the means to get the top rated computerized sewing machine in the marketplace, but if you jot down the main features which are most useful for your needs, you can get one which is worthwhile for your financial budget.
Manufacturers suggest that machines be cleaned and oiled every eight hours or so. Most hobby sewers dont sew for eight hours straight. (Though sometimes on deadline for a quilt show I have come close.) Maintaining your machine at the beginning of each new project is one way to remember. Even machines that are factory sealed benefit from frequent cleaning.
First and foremost check your owner's manual to be sure that you can clean and maintain your machine without voiding it's warranty. In general, newer computerized machines are factory sealed and maintenance is only allowed by a trained technician. If this is the case with your machine it is time to take your machine for its annual vacation to be cleaned and serviced. If you dont have your manual you can contact the shop where you bought your machine or the manufacturer, or search the Internet. A-1 sewing machine has links to free manuals online. Another site, Sewing Machine Reviewer offer links to all the major manufacturers. It offers links to free manuals, as well as, other models manuals that cost a few dollars. If you have misplaced your original manual this may be money well spent.
National Sewing Machine Day on August 12th is a good time to pamper your hardworking machine.
Please DONT blow into the machine to clean it out. Canned air used to clean computers seems to be an easy way to go but it can cause problems in the future. You dont want to force dirt and lint further into the machine. You want to remove it.
The best way to do this is to use a vacuum attachment that is sold for computers and electronics. It is basically a specialized miniaturized hose with small brushes that can get into the areas under your machine. It works great to remove all that fuzz that accumulates in the bobbin area.
And keep the outside of your machine clean, too. A cover at night, even if its only a lightweight cloth thrown over the machine, keeps out dust.
Keep your machine clean and it will serve you for years and years to come. I own a 1941 Singer Model 221 (commonly called a Featherweight) that I bought from its original owner years ago. 71 years old and still going strong. It has been lovingly maintained by the sewer/owners all that time.