Cinderella is a traditional tale which inspired cartoons, films, ballets and musicals. She only wears rags and old dress and she can't buy a new one. But one night something amazing happened: a fairy appeard and with a flick of her magic wand, Cinderella found herself wearing the most beautiful dress she had ever seen.

New and used could be:

A as ashtray
B as book
C as car
D as disposable dish
E as engine
F as filter
G as gum
H as handkerchief
I as icona
J as jeans
K as knife
L as lipstick
M as mop
N as newspaper
O as oxygen
P as pencil
Q as q-tips
R as raquet
S as syringe
T as ticket
U as underwear
V as vinyl 
W as waste
X as new X-men, a super hero comic book series
Y as year
Z as zip

We can say an object is new or used according to this different phenomena:

• wear
• fatigue
• stress
• life cycle
• operation time
• time between overhaul
• ageing
• time

Time:  is a one-dimensional quantity used to sequence events, to quantify the durations of events and the intervals between them, the ageing, and (used together with space) to quantify and measure the motions of objects.

Ageing: is the accumulation of changes in an organism or object over time.

TBO, time between overhaul: is a time 'recommended' by the manufacturer and depending upon how, for example, an aircraft is being operated. For aircraft used for non-commercial purposes overhauls are not mandatory, but highly recommended. Likewise, the TBO time recommended doesn't guarantee that the engine will last that long.

Operation time: The time interval between the instant of the occurrence of a specified input condition to a system and the instant of completion of a specified operation.

Life Cycle: is the time between an object's creation (also known as instantiation or construction) till the object is no longer used, and is destructed or freed

In continuum mechanics, stress is a measure of the internal forces acting within a deformable body. Quantitatively, it is a measure of the average force per unit area of a surface within the body on which internal forces act. These internal forces are produced between the particles in the body as a reaction to external forces applied on the body. Because the loaded deformable body is assumed to behave as a continuum, these internal forces are distributed continuously within the volume of the material body, and result in deformation of the body's shape. Beyond certain limits of material strength, this can lead to a permanent change of shape or physical failure. The dimension of stress is that of pressure, and therefore the SI unit for stress is the pascal (symbol Pa), which is equivalent to one newton (force) per square meter (unit area). In Imperial units, stress is measured in pound-force per square inch, which is abbreviated as psi.

Fatigue: in materials science, fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading. The nominal maximum stress values are less than the ultimate tensile stress limit, and may be below the yield stress limit of the material.
Fatigue occurs when a material is subjected to repeated loading and unloading. If the loads are above a certain threshold, microscopic cracks will begin to form at the surface. Eventually a crack will reach a critical size, and the structure will suddenly fracture. The shape of the structure will significantly affect the fatigue life; square holes or sharp corners will lead to elevated local stresses where fatigue cracks can initiate. Round holes and smooth transitions or fillets are therefore important to increase the fatigue strength of the structure.
In high-cycle fatigue situations, materials performance is commonly characterised by Wöhler curve: a graph of the magnitude of a cyclic stress against the logarithmic scale of cycles to failure.

Wear: in materials science, wear is the erosion of material from a solid surface by the action of another surface. It is related to surface interactions and more specifically the removal of material from a surface as a result of mechanical action. The need for mechanical action, in the form of contact due to relative motion, is an important distinction between mechanical wear and other processes with similar outcomes. The definition of wear does not include loss of dimension from plastic deformation, although wear has occurred despite no material removal, because it may lack the action of another surface. This definition also fails to include impact wear, where there is no sliding motion, cavitation, where the counterbody is a fluid, and corrosion, where the damage is due to chemical rather than mechanical action.
Wear can also be defined as a process in which interaction of the surfaces or bounding faces of a solid with its working environment results in dimensional loss of the solid, with or without loss of material. Aspects of the working environment which affect wear include loads (such as unidirectional sliding, reciprocating, rolling, and impact loads), speed, temperature, type of counterbody (solid, liquid, or gas), and type of contact (single phase or multiphase, in which the phases involved can be liquid plus solid particles plus gas bubbles).