Is anything ever complete?

What is complete or whole?

A car which is not missing any parts is surely complete or whole, by convention.

Buddhism is not concerned about this. It is only concerned with the fact that the car, as a conditioned thing is impermanent, and also the car as a phenomena that is not self and not belonging to a self.

When your car becomes damaged or has problems, this causes you suffering. It's not because it became incomplete. It's because it is impermanent, and you assumed it as belonging to your-self.

Please see the River Sutta. Please also see this answer for the longer story of the red car.

I think it's an observation or an axiom of Buddhism that things which are put together -- physically pieced together from components, and/or constructed in the mind -- they come apart again.

In this sense at least, things are not whole.

They are not permanent, they are subject to change -- and empty of "self", being "mere aggregates".

A thing might be complete though in another sense of the word "complete" -- not "finally constructed", but "finished", "undone" (deconstructed).

An action can be complete too -- finished, not continued -- "perfect" in the grammatical sense.

Arguably only what is not constructed (e.g. nibbana) is complete in being not subject to change.

I say "arguably", I think that various Buddhists over time made more and more of these "philosophical arguments" -- but the kind of statement I'm referencing here, about sankharas and nibbana, are mentioned even in the earliest tranche.

The last words of the Buddha were something like,

vayadhammā saṅkhārā appamādena sampādethā”ti
Conditions fall apart. Persist with diligence.

I've also seen (and remember) that translated as,

All compound things are subject to decay.

Conversely the first words of the Buddha include the following which I think are relevent here because they point to the possibility of an action or an intention, an endeavour, being completed:

This is the noble truth of suffering.’ Such was the vision, knowledge, wisdom, realization, and light that arose in me regarding teachings not learned before from another. ‘This noble truth of suffering should be completely understood.’ Such was the vision that arose in me … ‘This noble truth of suffering has been completely understood.’ Such was the vision that arose in me …

‘This is the noble truth of the origin of suffering.’ Such was the vision that arose in me … ‘This noble truth of the origin of suffering should be given up.’ Such was the vision that arose in me … ‘This noble truth of the origin of suffering has been given up.’ Such was the vision that arose in me …

‘This is the noble truth of the cessation of suffering.’ Such was the vision that arose in me … ‘This noble truth of the cessation of suffering should be realized.’ Such was the vision that arose in me … ‘This noble truth of the cessation of suffering has been realized.’ Such was the vision that arose in me …

‘This is the noble truth of the practice that leads to the cessation of suffering.’ Such was the vision that arose in me … ‘This noble truth of the practice that leads to the cessation of suffering should be developed.’ Such was the vision that arose in me … ‘This noble truth of the practice that leads to the cessation of suffering has been developed.’ Such was the vision, knowledge, wisdom, realization, and light that arose in me regarding teachings not learned before from another.

See also these suttas refencing a palmyra stump -- see also What is effluent? which I think is to do with the kind of mental habit or tendencies which keep people from finishing (or being finished) with things.

Arahat, once reached, means complete and Mahaparinibbana is the ultimate (comp)lete*, good householder. No use of seeking else, seeking of complete in the world. May good householder hurry up for it's gain, and such as philosophy will always be incomplete, a waste of time and effort, for the wise.

• *while meaning of complete in it's use might fit, the real meaning doesn't as real (comp)lete isn't compound.

[Note that this isn't given for stacks, exchange or what ever world-binding trade, but for Completeness.]

Everything is work in progress (becoming) except Nibbana (non-becoming) according to Buddhism.