I guess you want to know the medium of receiving energies in different ways.
Why do we need to energise Divine pictures or offerings with prosperity. The prosperity is required by human being not by gods.
You can request blessings to Divine directly through VK in your own words like praying to Divine with VK in your palms.
We do charge wallets and cards frequently,
Its not that threads/cards/wallets will be like a reservoir for two weeks, please read my post again, if your need of energy is high any reservoir will require replinishing daily or frequently.
No one can tell you how frequently these things would need to be charged in your case, as no one knows your requirement. Mostly it can be done once in a day to know that its daily charged..!!
Please go by your inner guidance, and take energies accordingly.