The key concept is placed-in-service date. It is the date the property is READY to be rented. Usually it is the time you placed the advertisement.
1. 房屋保險要換成出租屋的保險。
and you should also require tenant to purchase renter's insurnace.
2. 自主到出租房的轉換是在什麽時間點發生？假如是5月租出去，是不是到2026年5月之前賣都滿足2/5要求。
see above, placed in service date.
3 裝修費用如何報稅？
Any expense occurred before placed in service date is capital expenditure, can only be added to cost basis or depreciation basis. IBecause you spent X amount to get this house ready for rent, it's not on-going expense but initial aquisition cost that has to be added to cost basis for capital gain and deprecation basis.
4. 房屋如何折舊報稅？
The depreciation basis is the cost of aquisition, not the value of the house at the time of you moving out. Therefore, the depreciation basis is the value of the structure (not land) when you purchased this property + improvement made before place the property for rent.
It's 27.5 straight line depreciation. For partial year depreciation calculation, use a tax software.
5. 如果第一年，租金不多，需要房屋折舊嗎？
Yes. Don't be lazy. YOu have to keep track of depreciation and loss carryover in a spreadsheet througout the years of ownership so that you know how to deal with depreciation recapture at the time of the sale.
