You must read my articles with interest. The strength of houses is a combination of the strength of the Lord of the house, planets placed in the house and planets aspecting the house and the significator of the house duly moderated by the residential strength of the planets. Astrology is all about the strength of the 12 houses of a horoscope. The individual planets only contribute their might towards this ultimate purpose. The might of a country is the combined effect of their wealth, health and the government machinery. Is it not? All the planets in the Solar System has the same strength always but their influences on humans change depending on the time of birth. The combined effect of all planets acts on we humans as Dasas, Antardasa, Pratyanthardas, Sookshma dasa, Praana dasa and Deha dasa. Every breath of us carries the combined effect of all the planets in the above form. There is also the Narayana Dasa or Rasi Dasa which will help you evaluate the periods based on the strengths of houses. Read all my articles on the blog and you will be wiser.