We are spending one month in Spain. Any suggestions on how much cash I may need for general daily spending?
Spain can be inexpensive for food and lodging. Figure out how much money you have available to spend, then work out how much that comes to as a daily spending amount. I usually transfer funds into my checking account sufficient to cover my ATM withdrawals while in Europe. Then I pay almost everything in cash, including lodging. After paying for transportation and lodging, I probably don't spend more than 50 EU a day. Before trips, I often pay for train/plane travel in advance. While there I buy tix or passes for city transportation, with the occasional taxi. Using travel books I tally up what I expect to spend while traveling, then arrive in Europe with a rough estimate of how much it will cost. I withdraw funds from ATMs as I go along. Be sure to include the cost of museums, tours, events, etc. that you plan to enjoy. In sum, nobody can tell you how much money you need in Spain. But: don't scrimp. Go to the Alhambra, etc. even if it costs a bunch. If good meals are important to you, budget for them. You can get a good idea about how much things like that will cost by consulting a current guidebook.
Not really. It completely depends on your lifestyle, whether you will be eating out a lot or cooking, what kinds of activities you want to do, side trips, whether you will be using public transport or driving, etc. I was just in Spain for three weeks and spent between 0 and 100 euro a day, depending on where I was staying, who I was with and what I did. Prices there right now are generally cheaper than here for restaurant meals and food, if that helps. In reference to your topic title, though, I would take almost nothing along when I go, and just get money from the ATM at the airport when I arrived.