Diwali is not only a religious festival but it has also become people's festival. It is celebrated in various ways and with different perspectives. People celebrate it in their own ways.
Importance of Dhanteras…
Dhanteras is celebrated two days before Diwali. Many things are purchased on Dhanteras; people consider it to be the day for acquiring wealth. All these things are not in accordance with Jainism. According to Jainism, what is called as 'Dhanteras' is actually the day of renunciation by Bhagwan Mahavir. He had renunciated 'samavsaran' that day and situated himself at the center of the Padmasarovar lake in Pavanagar to stop yog (karmas). He did Kayotsarg to restrain and stop yog (karmas) for two days, and that was the time when lord Mahavir had renunciated wealth in the form of 'samavsaran' in true sense and entered into deep meditation. That day (Teras) became pure and auspicious because of his meditation, so it was actually 'Dhanyateras' which was converted into 'Dhanteras' by the people.
Buy metal on Dhanteras?
Don't think that if you buy some metal on 'Dhanteras' then it will bring prosperity in your house. This myth has been created by media/society and is influenced by priests and experts! What happens in countries where 'Dhanteras' is not celebrated? They are more advanced than us! However, if you want to celebrate something from a religious point of view and want something in return from a worldly perspective, then do not stop yourself to buy whatever you want to buy on any day.
Some people say that they are able to buy a few things because of Dhanteras. Alright buy things; it’s good that you buy a few things. But please be careful that you do not end-up buying useless things. Get rid of the belief that if you buy something on this particular date, then it will bring prosperity to your homes. If prosperity were to come by exchanging such materialistic things, then this world would have reached great heights by now! The true cause of prosperity is our internal karmas. Think of renunciating all the worldly possessions rather than amassing them. So Dhanteras should be celebrated in its real sense and so should be Diwali.
Importance of Diwali…
Diwali is a festival of lights, a popular festival filled with passion. True Diwali, as per Jainism, should be celebrated early in the morning when people offer laddoo in God Mahavir's feet. That is Diwali. Diwali, apart from being a religious festival, is also a very popular global festival, which is widely known as the Festival of Lights.
People clean up their houses on this day to get rid of the dirt or the negative energies from their houses. They also pray and worship their God. This means that they are doing something auspicious and getting rid of all the inauspicious and negative influences from their houses. This is the true feeling behind performing the rituals, So if you perform prayers, etc. in your homes or professional installations from a worldly perspective, then it s not prohibited from Jainism point of view. But we should be particular about worshiping of “Dev-Shastra-Guru” and God Mahavir - depicting detachment.
How to celebrate Diwali…
We have the provision of worshiping only the detached souls and not the ones which are still attached to emotions/materials. Therefore, we should worship only those who are detached and no one else. Read Mahavirashtak and Mangalashtak. Sprinkle rice and mustard all around after worshiping with the feeling that whatever negativity that is present nearby, it goes away. That we are able to spend our lives happily, peacefully and joyfully in the right direction.
Diwali is celebrated just on the day of no moon (amavasya). After eating food on 'Trayodashi' you must eat food only once or keep a fast and remember Bhagwan Mahavir. You must meditate about Bhagwan Mahavir on 'Trayodashi' and also on 'Chaturdashi'. And the day of Amavasya, when Bhagwan Mahavir attained Nirvana, early morning should be celebrated as Lord Mahavir's Nirvana Kalyanak Mahotsav. Wish that one should also be liberated from the cycle of birth and death. It will be the best Diwali ever. But if one cannot do this, then at least start worshipping Bhagwan Mahavir from that day onwards.
If you want to light lamps, etc. from a worldly perspective, then do so. But make sure and be careful that minimum violence is involved in the process. Do with the minimum possible that is necessary and you are able to do.
Importance of Small Diwali…
There is what is called as Small Diwali (choti diwali). Since this festival is an expression of passion & excitement, it is ensured that spirits are not dampened suddenly. You don't want your fervor to die down in a day or two. It should happen slowly. That may be the reason Diwali is celebrated for a day longer, no other reason seems reasonable beyond this.