In Islam, khums (Arabic: خُمْس Arabic pronunciation: [xums], literally 'one fifth') refers to the required religious obligation of any Muslims to pay one-fifth of their acquired wealth from certain sources toward specified causes. It is treated differently in Shia and Sunni Islam. This tax is paid to the imam, caliph or sultan, representing the state of Islam, for distribution between the orphans, the needy, and the [stranded] traveler.In Sunni Islam tradition, the scope of khums tax has been ghanim, which is defined as the spoils of war.
No unless the Marje' of Taqleed permits. Usually such works should be funded by the believers from their own money and not from the money of Khums which should go to the most deserving people.
You are not responsible for the Khums of the gifts received by you. You can eat the eatables. If it remains with you for a full year unused fully or partly, you will be responsible to pay the Khums of the remaining after full year if anything remains unused.
Yes. Khums is obligatory on us for any amount saved.
If you have any amount which remained after spending your usual lawful livelihood expenses, Khums will be obligatory in that amount, no matter how small it is. If all your income is spent on your usual lawful expenses and nothing remains, then no Khums on you.
Yes, as the extra amount is a new income which you have earned. If the value is less than what you have paid, then no Khums.
Islam does not allow the needy Sayeds to receive Zakat from people, and instead of that, kept for needy pious Sayeds a share in Khums. It is a matter of keeping the respect of the family of the Prophet (SAWA) with out any differentiation or discrimination. Non Sayed needy persons are allowed to receive Zakat while needy Sayeds are not allowed to receive Zakat. Justice requires providing a source away from Zakat to help needy Sayeds which is in fact Sahm e Sadat.
If it remains with you for one year, you should take out 20% of its current value.
Such amount is an income like any other income you get, which can be utilized for your livelihood along with your family and any reasonable expense. If on the day of your yearly Khums, any thing remains from it, just like any lawful income, that remaining amount will be applicable for Khums calculation.
Simply calculate your earnings then minus your lawful expenses and calculate what remained, then pay the Khums which is 20% of what remained from the earrings of every year.
Usual use of the cloth does not mean wearing it once or twice. Usual use means wearing it as one of your cloth which you usually wear.
If an item is not usually used for one year or more, then Khums is applicable on it or it's current value.
Donations which were already given are part of the expenses. Whatever amount which has been donated and given has gone out of your ownership, so there is no Khums on you for that donation because it has been given away and does not belong to you any more.
Your father did his duty by paying khums on what was liable for him. Once he transferred that amount to you, it now becomes your responsibility. In regards to gifts and khums, this depends on taqleed, so you will need to refer to your Marja' taqleed to see if khums is liable on gifts.
And Allah knows best