Dear colleagues,
in original article I see many many conceptual mistakes. Let me explain:
1) Photographer expects to shoot 20 weddings a year and live from that income the whole year. This is conceptually wrong. Even if you shoot 4 weddings per month and remaining time use for retouching photos you will spend maximum 5 months for that work. To spend 7 remaining months for marketing is too much luxury.
2) Equipment (camera / lens/etc.) costs should be depreciated during their useful life. 2 cameras - during 4 years, lenses - maybe during 6-8 years. If you shoot 20 weddings per year, your equipment should even last longer. Of course, here we might have moral depreciation issue, however, many wedding photographers still using their Canon 5DMKII and do not see any problem in that area

3) House, electricity, insurance, car costs calculated for the whole year. Which is wrong. One of the main accounting rule is that you have to match income and costs for the same periods. Accordingly expenses, that are attributable to that 5 montsh would be significant smaller.
4) Also, she attributes the whole house rent expenses instead of attributing small portion (garage rent costs) to business expenses.
In summary, she needs to do other activities / work during remaining 7 months in order to have sustainable income for the living. Not long ago I saw very good workshop "How to become 10k wedding photographer". Lecturer was prominent photog who makes 10k per wedding and he showed rough calculations which very clearly indicated that he needs to do a lot of other activities (he is doing photog workshops and lessons) in order to keep earn sufficient income for his living. In summary, it is very hard to live from photography only. You caan be successful photographer if you have another profession and photography is your serious hobby. In case you earn something from photography everything counts to profit

In my case I would be very have if my income from photography matches my equipment costs
Also, I would like to respond to comment who says that you need 10,000 hours to become really a pro. In such case you have to spend almost 5 full years (working 8 h a day, 22 days a month) learning photography secrets. I disagree with this statements as:
a) If you are really interested it is very easy to get technical knowledge that relates to equipment, how it operates, what are main principles of photography. There are many on-line and other course which lets you understand these aspects. For me it took maximum few months (during my free time from my main work as BIG 4 Audit director). Of course, I can not compare myself to such experts as Neuro or few others, however, my current technical knowledge is fully sufficient for photography.
b) Composition, lightning, ability to see that light. In order to master these things you need practice and tutor. I saw many cases when people became prominent photographers (especially wedding pros) after 2-3 seasons (they also have other full time jobs).
c) Photoshop - in my opinion, if you are seriously interested in retouching 2-3 months are more that sufficent to master that skills to acceptable level (for wedding photographers).
USD 3,000 / per wedding price is too high. Clients are not interested in your experience, equipment, lighting equipment, insurance. They want to buy specific product - wedding photos. Nobody cares about your expenses. If someone is doing wedding photography during weekends, has a good equipment and required skills he / she is able to make wedding photos much cheaper.
Surapon, I was very surprised that your sister paid USD 11,000 for wedding (not including indirect photog costs) and had to wait for such a long time. It seems that person is not a professional as real professional demonstrates professionalism in all aspects (communication with client, timely delivery of high quality results, significatly assissting in preparation for weddig ceremony). In my opinion, your sister significantly overpaid for taht services.