After the such installation of the draining pipes, if you see that in the bathroom, commode, kitchen sink and premises point, there is no problem/ signs of the storage of water, it means that your drainage is healthy and cleaning is not required still. If the position is otherwise, you find the stoppage of water at any point you should clean it through the proper tools or chemicals etc. When all the pipes of your drain have the same size, you would have not to keep different tools for emergency, only one tool e.g. plumbing snake would be sufficient for cleaning of all your draining pipes. Only the length of your pipe would be different, you should have the plumbing snake as long as the longest pipe of your draining.
The size of all the pipes should be sufficient/as per the expected quantity of water. For this purpose you would have to construct the wider space for the placement of the pipes. The ends of all pipes should be exposed when the lid of specific gutter/drain is lifted so that the disposal condition of all pipes should be seen. While checking the condition you should know how much quantity of water is being entered into the specific pipe from the other side. During this checking if you find improper flow/disposal of wastage from any pipe, you clearly know that which pipe is to be cleaned. From the speed of disposal of wastages from a specific pipe you can guess that if there is any soft clog or solid one and what is its size? You are able to decide that the chemical is essential to remove the clog or any plumbing tool is sufficient. Thus within no time the specific pipe of your drain would be clean.
If anybody has the objections on such draining system that due to the separate pipes it is a high priced. You should estimate the price of this draining piping as well as the general piping. Then compare both the prices each other, no considerable difference would be there because in this way the big size pipe to cover the wastages of all pipes is not used. Moreover if to some extent price is more than the general draining piping, you should also consider the cleaning charges of the general draining.