Shubh,
  I am talking about maturity which is different from old, young ,etc.
That would be the avastha of the planet.

Maturity is different. All planets have  an age when they mature.
For instance, Mercury matures at age 32. That means you can expect maximum benefit out of the planet at that age.
Ofcourse, the dasha also has to support the same.

The avastha also matters. If a planet is too old in your natal chart, it will not be strong enough to give results effectively.

Regarding combustion, there are no set clear rules but many eminent astrologers like BV Raman have given some theories from their experience which Shrikanthji put forward. So, like RRji mentioned, don't attribute everything to one factor like combustion.

Look at the different significations - from Asc, moon, dasha, transits, strength and come to any conclusion.

When the sun is a functional benefic as he is for Leo or Sagittarius lagnas for eg. unless he is in the same nakshatra pada or degree as the combust planet, rather than give malefic results, he would impart a benefic influence.

It is wrong to state that planets at start/end of sign are weak....if that were the case how can one consider Jupiter at his strongest in 3 deg Cancer or Mercury at the fag end of Virgo...similarly many planets give own house effects at the start or end of a sign when they are vargottama, which is considered a strong position. My study of charts in the start/end of signs have revealed tht they give the same results as a planet situated at 15 degrees or about the center of a sign, all other things being equal.

[quote="hedonist"]When the sun is a functional benefic as he is for Leo or Sagittarius lagnas for eg. unless he is in the same nakshatra pada or degree as the combust planet, rather than give malefic results, he would impart a benefic influence.[/quote]

Hello Hedonist,

Thanks for your posting and I agree with your message except for the portion where you indicated that if planet is in same pada EVEN with a benefic surya, it would suffer an affliction (due to combustion I suppose). ONLY if you are comfortable in doing so, if you could share with me privately or publicly an example of such being the case (planet combust and in close conjunction with benefic sun becoming afflicted), I would appreciate very much. Thank you,

[quote="rohiniranjan"][quote="hedonist"]When the sun is a functional benefic as he is for Leo or Sagittarius lagnas for eg. unless he is in the same nakshatra pada or degree as the combust planet, rather than give malefic results, he would impart a benefic influence.[/quote]

Hello Hedonist,

Thanks for your posting and I agree with your message except for the portion where you indicated that if planet is in same pada EVEN with a benefic surya, it would suffer an affliction (due to combustion I suppose). ONLY if you are comfortable in doing so, if you could share with me privately or publicly an example of such being the case (planet combust and in close conjunction with benefic sun becoming afflicted), I would appreciate very much. Thank you,[/quote]

Sun may be a functional benefic for some lagnas, but is a natural malefic or atleast a kroora graha  - and any planet in close conjunction with it would be said to be afflicted - or atleast facing the wrath - isnt it?