Thinking about taking AVE from Madrid to Cordoba and Seville and back. Should reservations be made? If so, how best to do it?

Only because a few years ago in Spain we had to wait half a day before seats were available would I suggest a reservation. You could try www.renfe.es/ingles, which is the english language page of the Spanish National Railways. I have not used it, but it seems user friendly enough and appears to have an online purchase feature you could reserve and purchase your tickets with a credit card. Or www.raileurope.com, which I have heard is more expensive, but is a US based service and which I have used at least for France can do the same and deliver your tickets in the US. At least on the renfe site you could check the price and compare to raileurope. Or, depending on your schedule, you could stop by the train station in Madrid a day or two in advance and make your reservation in person. It is nearby but not all that central to the major sites. Or maybe someone can suggest a local Madrid travel agent. I know at least in other cities in Europe travel agents can arrange and sell train tickets. For more about Madrid see www.madridman.com, a great website by someone who loves Madrid and Spain.

I think this depends on the time of year you're travelling. We were there over Easter and could not even get reservations on some trains because we hadn't booked in advance. (Infact it was the train from Seville to Madrid). So it depends.

AVE's are 'all reserved' trains. So you absolutely must have a reservation. Your query should probably be: how far in advance must one make a reservation. As artlover says: it depends on time of year and other factors.

There are three time-of-day based fares (Punto=peak; Llano=intermediate; and Valle=off peak) and three classes of service: Turista, Preferente and Club. Least expensive fares (Turista-Valle) sell out earliest. There are only one or two trains a day with that class available. I usually do Turista-llano. Departures are hourly from about 6 AM to 10 PM. Once, I had to ride in a 'smoking' section when I bought my ticket late and another time only Preferente was available. The last time I rode AVE I arrived to Sevilla at 8 AM on regional rail from Cadiz and had no problem buying my ticket & reservation (Turista-llano) for the 9 AM AVE to Madrid.

You should be OK buying your tickets & reservations a day or two in advance of your travel date. You can do that at the Renfe Office in Madrid's aeropuerto de Barajas or at the Renfe Office on c/Alcala (in Madrid) or at Puerta de Atocha or Chamartin station.

I was in Spain 3 years ago and bought tickets on AVE to Seville the day before we wanted to leave. We did the same in Seville on the way back to Madrid. It really wasn't a big deal, but it may have been an exception.

As has been said it depends on demand at the time you are traveling. We got "stuck" having to go preferente from Seville to Madrid because it was either that or smoking in tourista. This was making the reservation about 6 weeks ahead but this was during the April Fair in Seville.