Hi Skippy, cscotthendry is well on the right track.
The purpose of an aircraft maintenance schedule is to keep the aircraft in an "Airworthy Condition". What this means is that you will most likely never keep the aircraft in the condition it was the day it was built because of the aging process, coupled with normal wear and tear, accidents and incidents and the last is the owners attitude towards airworthiness. Lets look at these parts briefly.
AGING AIRCRAFT.
Since manufacture everything on this planet ages. Aircraft are no different. The Cessna SIDS program is one manufacturers process to help owners maintain airworthiness to address aging. CASA has some good information and some videos and DVDs on the subject. Look at your prospective purchase and check nuts, bolts, brackets and areas where water will accumulate after flight and check for corrosion or deformation. Types of corrosion will differ between the aircraft construction type. Composite aircraft fatigue different to Metal, which are different to wood, which are different to fabric. Check the Aircraft Maintenance Manual for any recommended Corrosion Protection or Inspection System. If there is not one, read AC43-13 about this subject.
NORMAL WEAR & TEAR
What the title says. The manufacturers aircraft maintenance schedule SHOULD provide a "Life Limit" or "Overhaul/Service Schedule" for individual parts that "WEAR". They typically wont do it for the carpet or the head liner or the windows but may provide limitations on parts of the aircraft that, If they fail, can place the aircraft in an "Un-Airworthy State". Items such as Fuel pumps, Engines, Propellers, Wing Attaching bolts and fitting on Aerobatic aircraft as given in the example used by Facthunter. Look at the ROTAX 5 Year Rubber Life requirement. Classic example.
Other parts or systems may not be listed in the AMM and are required by Legislation, such as CAO100.5 system checks. Does your Pitot/Static system work correctly, is your Transponder System calibrated correctly and so on. Also, associated are Airworthiness Directives and RAAus AN's. These mandatory requirements are derrived due to past accidents and incident and are there to help you maintain your aircraft in an "AIRWORTHY STATE".
ACCIDENT & INCIDENTS
If the aircraft has been damaged, then it needs to be repaired IAW (in accordance with) "Approved or Acceptable Data:. These should be recorded in the aircraft records.
OWNERS ATTITUDE
Like buying a used car, you can tell pretty quick if the owner has maintained their aircraft appropriately. Some people are anal and do things correctly (some to extreme and they do almost resemble the new aircraft) and some wont spend 5cents on their aircraft. Seen both and it shows.
OVERVIEW
I would think that a reputable flying school would have well maintained aircraft that keep them in an "AIRWORTHY STATE". Do your homework, download the prospective AMM (Aircraft Maintenance Manual) and get yourself a list of all the tasks associated with the aircraft, research AD,s AN,s and Service Bulletins for Aircraft, Engine, Propeller and installed components by the individual serial number. THEN, check the aircraft records. I mean REALLY checkout the aircraft records. Ask for a "Maintenance Run-out Sheet or Maintenance Due List" to find out when all the aircraft maintenance was last done, who it was done by and how long is remaining for each task.
The only thing I will suggest is DO get a Pre-Purchase Inspection. A proper one. DO NOT get the maintainer who has looked after the aircraft for the last 10years. He will be "Too Familiar" with the aircraft.
I have attached an article I wrote many years ago and it is still relevant. If you would like help, contact us as we can do the complete Maintenance Requirement list for you based on the aircraft and component serial numbers you provide. BUYING A PLANE ARTICLE.pdf