The following are preventive maintenance checks/replacements:
1) Vehicle multi point checks.( Suspension, steering, tyres, brakes, exhaust system)
2) Brake pad/shoes check/replacement.
3) Coolant replacement, thermostatic valve replacement.
4) PCV valve replacement.
5) Brake system flushing and fluid replacement.
6) Transmission oil and filter change.
7) Radiator upper/lower hose check/replacement.
8) Tie-rod end check/replacement.
9) Air filter cleaning/replacement.
10) Sparkplug replacement.
11)A/C cabin filter replacement.
12) Timing belt replacement.(if equipped)
13) Surpentine belt replacement.
Most of the above replacements are done at specified change intervals as part of preventive maintenance.