Nhattrungluu asks if 'Student' should have written one paragraph about the advantages of pets and one about the disadvantages.

The problem is that there are so many sub-questions in the question and this makes the question very difficult or impossible to answer.

Let's look at the question again:

In western countries people spend a lot of money on their pets. They buy special food for their cats or dogs, buy them toys and often pay high fees for medical treatment. Some people think this is a waste of money, and argue that pets are dirty and dangerous. What are the advantages and disadvantage of having pets? Do people spend too much money on pets? Give reasons for your answer.

So what is the real question here? Is it advantages and disadvantages of pets? Is it whether people spend too much on pets? Are pets a waste of money? Is Fluffy a potential killer, and is cute little Fido who shares your decadent Western bed a teeming mass of dirty hair, fleas and tapeworms?

I really don't think this is a real IELTS question, and I'm sorry that 'Student' had to spend time answering it. IELTS questions are much clearer, simpler and shorter than this. I can't blame anyone if they don't know how to answer this question.

I think that 'Student' did a reasonable job with such a crazy question, but it's impossible for us to say if the layout is good or not because of the problem with the question.

However...

Did nobody notice that 'Student's' essay is only 216 words long?  This would be a big problem. Make sure that you reach the magic 250 words!

Three Essay Topics: A, B and C

It's a shame to abandon this topic of pets. Here's an IELTS essay topic, supposedly from Bahrain in 2011. Let's call it Topic A

Some people believe that keeping pets is beneficial while others believe it is a bad idea. Discuss both views and include your own opinion.

Again, I wonder is this the real original wording. Anyway it's a much simpler essay. Anyone want to try it? You can see an example answer here (with a lot of errors)

Here's another topic. Let's call it Topic B

Too much attention is paid to and too much money is spent on keeping pets, while people throughout the world are starving. Discuss the arguments for and against keeping pets

and here's an answer here, also with a lot of problems.

Finally, here's a third topic. Let's call it Topic C

Many people have a close relationship with their pets. These people treat their birds, cats, or other animals as members of their family. In your opinion, are such relationships good? Why or why not? Use specific reasons and examples to support your answer.

...and here's an interesting answer!

If anyone wants to try any of these topics, that would be more useful than spending more time on the essay above. 'Student,' if you have time, it would be great to see a new essay from you on Topic A, B or C!

If anyone does try, don't post here. Just make a new topic and copy and paste the question.

Here are some tags you can copy-and-paste as well

animals, pets, nature, health, poverty, companionship, waste, affluence, lifestyle, hunger, affection, fun

Every day, thousands (thousands of) people die due to hunger. Although modern society waste their unnecessary money on their pets.

Fragment. 

Although thousands of people die everyday due to hunger, some people living in developed areas waste their money on pets.

(add "However" here) This money could be spent on food for people. It is said that pets may spread lots of(many kinds of. "lots of" has been used many times)disease because they are dirty . They need extra care and regular treatment. We cannot live (leave) them alone in home for long time  (a long time).  Thus people have to spend lots of money and time for their pets.

My suggestion

I read your essay twice, I can't see your reasons why you think people spend too much money on pets. You just wrote that a lot of people die because others spend too much on pets.

Is that a supported reason? I don't think so. You see, I can also say: Although a lot of people die because of hunger, the riches waste money on collecting luxurious cars. So what you wrote, in my view, only can prove that people are ignoring the poor in remote areas, but cannot prove the money are being wasting on pets.

You can give an example, like--Usually, a family spend (?) dollars on raising pets per month, which is equal to/which is afford to buy (?).  Just show some evidences.

Generally, people are interested for (interested in) keeping pets in their home not only in developed countries but also in other countries.

Word order (Sequence)

Generally, not only the people in developed countries but also those in developing countries are interested in keeping pets in their home.

Having pets in home is the (a) fashion of(to/for) some people and they are happy to play with pets. They are wasting(waste)lots of money for facilities of their pets like cats, dogs, horses. It is argued(debated) that This is not good to spend lots of money on pets. Sometime pets may bite people so they are also (could also be) dangerous for people. (Not all the animals are dangerous so try to use "subjunctive mood".)

INTRO.

Your grammar here is fine and I didn't see many erros here. But somehow I feel that your sentences are too easy. I mean, the sentences structures and some of the prases you used, such as "lots of money", " happy to play with pets", "this is not good to".

I know what you mean in the intro., but it gives me a feeling that it was wrote by a ninth-grade student (sorry). So I think you can express your idea in a more advanced way. Here I am not meaning that you need to use the academic vocabulary as more as possible. I mean your mean of expression. Below is an example, only for your reference.

You wrote— Having pets in home is the fashion of some people and they are happy to play with pets.

Raising pets is a kind of fashion for some people and they enjoy the company of pets.

Generally, people are interested for keeping pets in their home not only in developed countries but also in other countries. Having pets in home is the fashion of some people and they are happy to play with pets. They are wasting lots of money for facilities of their pets like cats, dogs, horses. It is argued that This is not good to spend lots of money on pets. Sometime pets may bite people so they are also dangerous for people.

Every day, thousands  people die due to hunger. Although modern society waste their unnecessary money on their pets. This money could be spent on food for people. It is said that pets may spread lots of disease because they are dirty . They need extra care and regular treatment. We cannot live them alone in home for long time. Thus people have to spend lots of money and time for their pets.

          However, pets are an excellent way of spending our leisure time. People can train their pets easily because they are more friendly and interactive. Usually human foods are suitable for pets so people may not worry about their food. People gets the opportunity to learn about these animals, their like and dislikes. Pets need everything like food, treatment in time therefore it makes people more responsible. People can also earn extra money by doing business of pets for example Zoo, keeping and buying their child pets.

In conclusion, people who love pets they should care of their pets. But that is not meant to waste their time and money a lot. People should manage their responsibilities and time.