Saving your hard earned money

A scheduled maintenance is required to maintain the printer's performance. To do this, you need to install the proper maintenance kit.

yes if you go to the instr. manual you will find in section maintenance the properly schedule.
God bless you.
download the instr.manual from www.retrevo.com give you model, serial number, +marks

 STEERING/FRONT SUSPENSION: CHECK
• Maintains integrity of steering and suspension components, and
assures proper wear
 REAR SUSPENSION: CHECK FOR WEAR
• Maintains integrity of suspension components, and assures
proper wear
 DRIVESHAFT JOINTS: CHECK FOR WEAR/PLAY
 DRIVESHAFT: CHECK BOOTS
• Assures proper wear and that foreign matter does not contaminate
drive shaft joints
 PROPELLER SHAFT, PILOT BEARING AND
UNIVERSAL JOINTS: CHECK WEAR
AWD models only
• Helps assure proper all wheel drive performance
 EXHAUST SYSTEM: CHECK FOR DAMAGE/LEAKS
• Maintains quiet operation and proper emission control
 SPARK PLUGS: REPLACE
Except engine VIN code 85
• New spark plugs are specially designed and calibrated to provide
optimum engine operation.
• Engine is tested on special Volvo equipment after spark plug installation

 PREVENTATIVE maintenance is to assure a smooth running, efficient low cost car.   
Now on the subject of using regular all the time, you do not want a buildup of carbon in your intake manifold(the lungs of the engine) so as not to "clog" or damage the emmission sensors and valves that can cost plenty to replace.
 A carbonized intake manifold could cause as much as $1000.00 worth of repairs to have to be done. So spending approx. $150.00 to do a fuel injector & induction service seems a less expensive alternative.
Also it would pay you in the long run to put in a tank of super every three or four tankfuls, with a can of fuel injector cleaner at that time. 
Remember, it is better to spend a little bit extra now than hundreds later. Now said, to replace 3 EGR sensors and valve, plus have to do an intake induction service on top of all that. So be smart, do your PM's regularly but i think just by running fuel injector cleaner every 1,500 miles would be fine. Take care and I hope this helps.

I own a 1994 Buick LeSabre. I purchased this car brand new. I now have over 150K on the car and other than replacing the tires, fuel filter, plugs and and alternator (with the exception of the tire, all other work was all done by myself), this car it has not given me any trouble. The bottom line, if you properly maintain a car, any car, it will be very reliable. In fact, I have owned several cars (9 to be exact) and they all have given me little trouble. Maintenance, maintenance, & maintenance!