There are two ways in which the Lord can come to you: by your own intention and getting a blessing for that from your Guru (then you can buy the Deities/receive Them, etc.); or by His own will (when the Deities are gifted to you/any other situation that leads to that). In the case of the latter, it is better to not refuse the Lord and, if it is possible, to warmly welcome Him. But if you are really not able to take care of the Deities, then best is to try to give them to any other devotee. The Deities cannot be thrown away/broken, etc.
The Lord is one and the same but He appears in different forms (that are confirmed by sastra). He is also in our hearts, in each atom, in each object, but there are particular forms that are His full forms. And each of them has to be worshipped accordingly.
Why is it so? The forms that require the simplest worship do not accept offence when mistakes are made, but the higher you go, the more attentive you have to become. Srila Prabhupada always said that if you are going to welcome Sri Krishna to your house, you need to be ready to commit. Otherwise, it’s better to have only pictures or Deities of Sri Sri Gaura-Nitai who are the most merciful incarnations of the Lord.
The simple worship consists of: offering some food preparations according to your schedule (at least once a day), at least one arati a day; singing Hare Krishna kirtan for Them or reading the scriptures. Bathing/dressing/putting the Deities to sleep is optional. It does not have to be elaborate. It all depends on how many family members are involved and what kind of standard you can maintain.
If you would like to increase the standard of your Deity worship, please get advice from your spiritual master or local authorities.
Once your altar is ready, you are advised to do a regular and continuous worship.