I just started to make reservations for hotels in Florence and Venice for travel in Sept. of this year (I know it is late). I noticed that most of the b&b which replied all say -payment in cash. Is that customary or just because it is 90E/double room with insuite or at times shared bath? Venice states 3/person/night tax, is Florence the same rate for the tax which again states will be in cash.
The use and demand for cash in Europe is far more frequent than in the US. Often you can get a discount for using cash and sometimes a surcharge will be added if you use a credit card. The style or type of room has no effect on whether cash is required or not. Each city has it own tax rate just as in the US. Many hotels will require a credit card number to hold reservation even if they require payment in cash.
Yes, it is common for hotels, especially smaller establishments like B&B's, to take cash only. Just plan for this by going to the ATM for a few days in a row before check out, and keeping the money in your moneybelt.
Also check if they are requesting cash for the room or just for the tax. Some (most?) cities are now imposing a €1-2/night tax that has to be paid in cash, even when paying by cc for the room.
We have gone to Europe every summer for a month the last 10 years (leave again Aug 31). We have used credit cards very few time, maybe 5 total. We always prefer to pay cash when required or when we ask if there is a discount for paying cash - which there often is. We choose to stay in B&Bs wherever possible and if none are available, we try to find a small, family run hotel. Happy travels