Godt vedlikehold bidrar til lang levetid og energibesparelse.

Because vedlikehold is a neuter noun: et vedlikehold.
In Norwegian, adjectives must agree with the noun:

• en god bil
• et godt vedlikehold

So godt is the correct neuter form of god here.

Because vedlikehold is often used as an uncountable or general abstract noun, much like maintenance in English.

So:

• Godt vedlikehold er viktig = Good maintenance is important

You would not normally need et here unless you were talking about one specific instance or type of maintenance in a more concrete way.

Vedlikehold means maintenance or upkeep.

It is a noun, not a verb.
Related forms are:

• å vedlikeholde = to maintain
• vedlikehold = maintenance

So the sentence is talking about maintenance as a general practice.

Bidrar til means contributes to.

The verb is å bidra = to contribute, and it commonly goes with til when you say what something contributes to:

• bidra til bedre helse = contribute to better health
• bidra til lavere kostnader = contribute to lower costs

So:

• Godt vedlikehold bidrar til ... = Good maintenance contributes to ...

Yes, but it depends on the structure.

Common patterns are:

• bidra til noe = contribute to something
• bidra med noe = contribute with something / provide something
• bidra on its own = contribute

Examples:

• Dette bidrar til bedre resultater
• Han bidrar med erfaring
• Alle må bidra

In your sentence, til is necessary because it introduces the result or effect.

Because levetid is a common-gender noun: en levetid.

For common-gender singular nouns, the adjective form is:

• lang levetid
• god idé
• høy kvalitet

The form langt would be used with a neuter singular noun, for example:

• et langt liv

So lang levetid is correct.

Yes, levetid is a compound noun:

• leve = live
• tid = time

Together, levetid means lifetime, service life, or lifespan, depending on context.

In a sentence about maintenance, it usually means service life or lifespan of a machine, building, or system.

Because both are being used in a general, abstract sense.

Norwegian often leaves out the article in this kind of statement:

• bidrar til lang levetid
• fører til bedre kvalitet
• gir høyere effektivitet

This is similar to English phrases like:

• contributes to long life
• leads to better quality
• gives higher efficiency

If you made them more specific, an article could appear.

Exactly. Norwegian very often combines nouns into one word.

Energibesparelse can be understood as:

• energi = energy
• besparelse = saving / reduction

Together: energy saving or energy savings

This is very typical in Norwegian. English often writes similar ideas as two words, but Norwegian usually prefers one compound noun.

Norwegian often uses the singular abstract noun where English may prefer a plural.

So:

• energibesparelse can mean energy saving in a general sense
• in natural English, that may become energy savings

Both languages are being natural in their own way. A literal one-to-one match in number is not always necessary.

Yes. The preposition til covers both items in the list:

• til lang levetid
• og energibesparelse

This is the same as in English:

• contributes to long service life and energy savings

You do not need to repeat til before the second noun unless you want extra emphasis or clarity.

Yes. It follows normal declarative main clause word order:

• Godt vedlikehold = subject
• bidrar = verb
• til lang levetid og energibesparelse = prepositional phrase

So it is a very standard pattern:

Subject + verb + rest of the sentence

This is one of the most common sentence structures in Norwegian.

Yes, in many contexts you could, but the tone changes slightly.

• godt vedlikehold = good/proper maintenance
• bra vedlikehold = good maintenance, more everyday and informal

Godt vedlikehold often sounds a bit more formal, professional, or technical, which fits this sentence well.

Here it is an adjective.

It describes the noun vedlikehold, so it must agree with that noun:

• et godt vedlikehold

The form godt can also be an adverb in other sentences, but not here.
In this sentence, it is clearly the neuter singular adjective form of god.