Every family must perform puja to Isvara. Those who find it convenient to do so may conduct elaborate types of puja after receiving proper initiation into them. Others need perform only a brief puja, not lasting more than ten minutes or so. Office goers must offer at least this brief worship. The sacred bell must ring in every home. Images must be installed to worship Siva, Amba, Visnu, Vinayaka, and Surya. This is called "pancayatana puja".
According to one custom, no graven images [images with limbs] are used but instead natural objects to represent the five deities. The "bana-linga" for Siva is obtained from the Omkara -kunda of the Narmada River. The svarnamukhi stone for Ambika (it has a golden streak on it) is to be taken from the bed of the Svarnamukhi river in Andhra Prades. The symbol of Vishnu, salagrama, is obtained from the Gandaki River in Nepal. The crystal stone for surya is got from Vallam, near Tanjavur. The sonabhadra stone for Vinayaka is obtained from the Sone River, a tributary of the Ganga. These five stones are symbolic of the unity of India. None of these five stones has eyes, nose, ears, etc. Since they have no corners that become untidy, they are easy to bathe and dry. Being small they do not occupy much space.
No big puja hall or room is necessary. A small casket is enough. Pancayatana puja was revived by Sankara Bhagavatpada. As the creator of the Sanmata system (the worship of six deities)he added Subrahmanya to the five. So with the five stones we may add a small spear to represent Velayadah (Subrahmanya) who bears the spear. Not much effort is needed for the puja. If you have the will, it could be performed wherever you happen to be.
At home when you do the puja you have to present to the deities cooked rice called "maha-naivedya". The Lord has created the entire cosmos for our sake. Our sense organs take delight in the various objects in creation. All that gives us joy, all that is beneficial in creation, must be offered to the Lord [symbolically] before being partaken of by us. When we offer any food as naivedya to Him, do we really give it away to Him? We just place it before Him and then partake of it ourselves. Some ask, scornfully, whether the Lord himself eats what is offered to Him. "Nivedana"does not mean making the Lord really "eat" what is offered. He does not have to eat.
Puja is meant to make us inwardly pure and the Lord does not have anything to gain from it. "Nivedayami" means I am making it know to you (informing you)" and does not mean "I am feeding you". You must speak thus to Isvara:"O Lord, in your compassion you have given us this food." Then you must eat the food thus offered, thinking of Him. Without His grace how does the rice grow? Experts may conduct research and write big tomes on rice. But are they capable of making one grain of rice? What is called synthetic rice is made out of materials already created by Isvara. So all that seems to be made of man must be finally traced to God's creation. To enjoy what he has given us without first presenting it to Him would be tantamount to thieving. He who is present everywhere must be present where we want Him to be present so that He may be grasped by us. Whatever the material out of which His image of symbol is made-stone, earth, copper- he will come to us in that material and in that image or symbol. He will do so out of His compassion and He has the power to do so. We would have no need for him otherwise.
The Lord must be worshipped in every home. He must be invoked and it must be made known to Him that we are using nothing but what he has made over as a gift to us. If we keep doing so, we will in due course have the wisdom not to use in puja things not fit to be offered to Him. We ourselves will come to possess good qualities.