'to' vs 'for': Planing is important for/to long-term success

[Ganesh]

Planing is important 'for' long-term success

Planing is important 'to' long-term success

[Milanya]

Strictly IMO

Important to - I feel it is important - Planning for a long-term success is important to me. - I feel that planning is important in order to achieve success.
Important for - will bring a result - Planing is important for (achieving) a long-term success - You need to plan ahead in order to achieve success.
Importan to is also used when important is followed by an infinitive:
It is important to study ....
It is important to know..., etc.
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con·text - The part of a text or statement that surrounds a particular word or passage and determines its meaning.