They are very important, in the same sense that the timing on launching a business, starting a project, buying or selling something is important. It is very important to find the best time to do certain things, and the astrology of the launching of things is an art in itself.
That said, it is impossible to counteract "real world" conditions. For instance, you can plant potatoes on the best day of the month astrologically, but will probably not get many potatoes if you've planted in November rather than April.
By the same token, you may get a great deal on a house, but if the house has plumbing problems, you'll still have to deal with them. And yes, plumbing (or electrical, or foundation) problems can be seen in the chart of when you first look at a house, as well as when you close escrow.
Most people think that a compatibility chart tells all there is to know about whether two people are suited to each other. While extremely important and revealing of points of harmony and conflict, other important charts include the time when two people first meet, as well as the composite chart.
The composite chart is derived from the midpoints of the similar planets between two charts, i.e., if one is an Aquarius and the other is a Gemini, as a rule the composite Sun will be in Aries. And if one Moon is in Sagittarius and the other Moon is in Aquarius, the composite Moon is likely in Capricorn, the sign in between Sag and Aquarius.
Then there's the marriage chart. This is actually an Inceptional chart, in that a marriage is the inception of the contract of partnership. Thus it shows the past, present, and future of the individuals, as well as the composite unit.
In any marriage chart it is good to make sure that the rulers of the two people getting married are harmoniously aspected with each other, and if possible, the rulers of each's marriage house (7th house). FYI, "love affairs" are ruled by the 5th house, not the 7th. That's why even if one has a boyfriend or girlfriend for years but has never married, then it cannot be counted as a 7th house activity.
The first marriage is ruled by the 7th house, as are all partnership circumstances throughout the life. The second marriage is ruled by the 9th house, the third marriage by the 11th house, and so on. This is the source of much confusion among amateur astrologers and novices at the craft, and the reason I ask people who come to me for a wedding date whether they've been married before or not.
If I'm planning someone's second wedding, then their significator is the ruler of their 9th house and any planets in that house, and the 7th becomes more of a secondary and even generic influence.
And on a final note, the week of July 11, 2005 was a great week for getting married, since there were many favorable aspects made between the rulers of many signs. I know of several weddings for that week, and somehow it also seems that Jupiter in Libra has brought more marriages to the fore than I remember in other years.
Maybe Libra, the sign of marriage and partnership, is somehow expanded by Jupiter into a hopefulness and an adventure in partnership. Maybe marriages under the influence of Jupiter in Libra are somehow the archetype of what the higher truth of relationship is really all about. So if you were wondering, it was a great week to elope and a great time to get married. There are also other great days coming, but that's another article for another time.
BIO: Robert Wilkinson is the author and astrologer of www.aquariuspapers.com. Robert's scholarly work is fascinating and understandable to even non-astrologers. He explores the big picture about factors that affect us all. He believes that each of us has our own pace and challenges, but by understanding what is personal and what is common to us all, we can avoid creating unnecessary problems for ourselves. Visit Robert's blog for his current take on how the planets are influencing us now.
If you'd like an astrology reading, Robert can be contacted to set up an appointment for you by Email or Phone (310) 312-1803. He is also available for speaking engagements.