PREFACE
At about 4 years ago, occasionally i found a destiny forum website in china, considerable serious but still healthy atmosphere for discussion, i dropped by for a short period time participating in the bazi reading for life destiny enquiries from reader members.As my reply always started with " i am not a da-si (big master) but just a visitor passed by and come across your enquiry, nevertheless i would like to share with my view. ". Since then,the members began to often address me as "pass-by da-si" requesting me for answer and viewpoints. Below is ine of the enquiry case.
CASE
Enquiry from a member asking for advice from the teachers here, about the below bazi daymaster is considered strong or weak? What is the useful god and happy god? Why?
4-pillars:
公历：1932年12月23日06时 虚岁： 命主今年80岁 person is now 80 yrs old　　　 偏财　　　偏财　　　日柱　　　正官
        Year            Month        Day            Time
乾造：　壬　　　　壬　　　　戊　　　　乙
Male   　申　　　　子　　　　午　　　　卯　　　　空亡(子丑)
>　　 

10-yrs luck yun
大运：癸丑　　甲寅　　乙卯　　丙辰　　丁巳　　戊午　　己未　　庚申
实岁：05岁　　15岁　　25岁　　35岁　　45岁　　55岁　　65岁　　75岁　　
My reply:
How are you, I am not dai-si ( big master ) but  just an ordinary member passing-by, hope you don't mind . Daymaster is strong or weak? This can easily come into arguements, due to  there is no publuc recognised standard to be based on for judgment.
Looking at this life, born in lunar calendar 10th month 23rd day, Ren water has passed its extreme strong turning into weak, Gui and Xin retreating but Ji earth is at power. (So daymaster Wu earth seem strong? )
Look further, the daymaster Wu sitting on Wu resource as yang knife seem extreme strong , however near to the EB Wu fire is the year and month EB Zi Shen half  3-Unity water which penetrates up to the double HS Ren resulting into strong water into a powerful killing force to the Wu fire. When day EB Wu fire is being trapped and attracked by such strong water, it become unable to take care and give support to the daymaster Wu earth on top.  While the time HS Yi sitting on EB Mao as "treasure", into strong wood with water feed and fire warm body, being a strong OF to the daymaster.
Therefore, I define this daymaster as weak. Happy and useful god would be wood and fire to enpower the daymaster earth so as to be able to take in the strong wealth (water).
Regardless of strong or weak, this life 4pillars' 5 element qi is clear and pure, the wood and fire would bring alive qi to the person. As such, run on the south-east seasonal 10-years luck yun qi, is considered a very good life on good luck yun, high-govt offiical or noble life type.
10-years luck yun at south-east wood fire yun 甲寅-己未：age 15-74, so good life good luck yun, this is hardly encountered in life.
Look further, the Jia yun (age 15-24) is mixed OF and 7K where such mix 犯官杀混杂 could cause him into big trouble, hard bad luck in life and living, this was not yet to his life at fatal dangerous or failure time, because the Yun Jia is siting on EB Yin which is being trapped resulting no strength too feed Jia.  OF Jia might be able to disburb 7K Yi but still unable to replace 7K.   
Since the wood fire would be the happy useful god, the opposite would be metal water as the anoying god. For example, entering into  Geng Shen Yun 庚申运, the 10-years luck yun, by the time the person will be already aged over 70 above, life as such should have no regret no complaint already.
The feedback obtained:
This person has been a high-govt official, life before Jia yun was very bad and down, Yin yun (starts at age 20)  onwards all the way had been going very smooth and successful, before entering into the Geng Shen yun (start at age 75)
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几年前作客一大陆术数网站，有一网友发问以下之八字:
公历：1932年12月23日06时 虚岁：命主今年80岁
　　　 偏财　　　偏财　　　日柱　　　正官　　　
乾造：　壬　　　　壬　　　　戊　　　　乙
　　　　申　　　　子　　　　午　　　　卯　　　　空亡(子丑)-
　　　正财　　偏官　　正官　　偏印　　正印　　比肩　　劫财　　食神　　
大运：癸丑　　甲寅　　乙卯　　丙辰　　丁巳　　戊午　　己未　　庚申
实岁：05岁　　15岁　　25岁　　35岁　　45岁　　55岁　　65岁　　75岁　　
请各位高人指教这个八字是身强还是身弱，喜用神是什么？为什么？
我推算: 
你好，我非高人也非大师，只路人。希望不介意吧。身旺身弱，易为争议，无一定公认的标准可评定。试看这命造，出生于十天月二十三日，壬水旺极转衰，癸辛退而己土主权。然而日主戊坐午印阳刃，但旁被月年支子申半水局透出双壬所强冲，日支午火被此强力冲绊著，又何能亦无闲去生助日干戊土。而时柱乙木官星坐禄卯，亦自身强午火取暖子水生身。故我论日主戊土为身弱。喜用故为木火去生身以能身旺纳财吧。然而，此命造八字清而气纯，而运行东南，好命好运，贵也。
其实，无所谓身强或弱，也不分上下，以木火令其生气流动多活力为贵。运行东南，木火大运：甲寅-己未：15-74岁,好命好运, 人生几何！再看，其甲运虽犯官杀混杂之弊，但并非至危败之运，因甲坐寅支根受绊住无力，甲能扰乙官而未能夺官。既木火为喜用，其相反者即金水为忌神，如入庚申运，然人已临高龄七十多，无憾矣！
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The feedback: 
此人为一机关工作人物，甲运前不利，寅运起一路顺畅至庚申运前。
http://tiensum.blogspot.sg/
AFTERWORD
since the member asked specific about whether the daymaster is determined as strong or weak, and what are the happy gid and useful god, and why so. This member surely knows the bazi science so why question was into technical-know-how. For the reason, my answer was into the technical ways, using the bazi jargons and terminology. Otherwise, I would avoid answering as such due to not easy for general public people understanding.