Planets and yogas activation

[music_man]

I watched this show the other day where an astrologer was mentioning about a set time scale for the activation of planets.
Like for example, Mercury gets activated by a certain age, say 28. When this happens, it would hence further activate all planets it is aspecting and houses it is lording, and starts a chain reaction.

If this is true,
1. Does the fact that this activation only takes place at a certain time, deny you of any promised karmic benefits that planet was supposed to deliver? ( Similar to saying you would probably never experience benefits of a certain yoga if the said period/sub period doesn't operate in your lifetime.)
2. Please post any charts that you know of where such an activation took place.
It would be helpful if we are more specific as to what significations promised by the planets got activated, rather than a more holistic approach.

Could any learned members comment on this.

[Aravind]

Mercury is considered a prince in Vedic astrology that is why it is commonly believed that if the Mercury Maha Dasha gets activated in your teens it might give very positive results especially in your education provided it is well placed both by sign and house. Similarly Saturn is considered as an old man and hence a Saturn dasha starting after 40 might gove better results. This doesn't mean those planets will not give great benefits if they get activated at any other time but they might give maximum positive effect during a certain age provided they are also placed well in the chart.

Thanks
Aravind