Very good advice. Unfortunately, those of you in smaller markets are likely out of luck. No one else AFAIK refunds 100% of a fare for credit on a future flight when you have to change a reservation for any reason.
Another way I saved money was to book one trip with multiple flights once I had confirmation of a few dates around each other, instead of flying back and forth from home.
Few other money saving tips I discovered:
1) Third the southwest suggestion, use this as often as you can for the reasons outlined above. The Priority boarding for $12.50 is sort of a rip off, but make sure you do it for the legs of trips where you will be busy 24 hours before the flight. I was often at interview dinners when I was supposed to check in, and got in the low B group a couple times, which made it dicey to get overhead bin space for my suits. So, if you know you'll be busy, cough up for the priority boarding.
2) Kayak.com and southwest.com should be the two sites you used to find the cheapest airfares. Kayak aggregates nearly all the airlines except southwest and jetblue, so is a great resource to figure out which airline has the cheapest flights to where you are going. I highly recommend Delta if you can find it, if your flight is delayed even 5 minutes, you can move up to an earlier flight for FREE. This got me out of some dinky airports and home earlier at least a few times. Also you can make these changes from the delta app, very easy.
3) Hotwire.com for hotels and car rentals during the couple weeks leading up to your trip. Hotwire, aim for the three star hotels because they often come with free parking, Wi-fi and breakfast. The four stars are tempting (I did this a few times) and then paid $40 for parking and $10 for wi-fi, ugh.
4) Rental cars through hotwire are amazing. I often paid far less than my co-applicants who took taxis, so don't automatically assume that taxi's are cheaper!
5) For men, check out Jos. A Bank, I got three suits for the price of one before interview season. This was very useful for the middle of december when you have so many interviews in a row you don't have time to dry clean your suit.
6) Travel tip - If your ideal garment bag is too big, remember that you can "gate check" for free as well. This cuts out the middle man, so they take it from the ramp onto the plane, and then you pick it up at the ramp again. Personally, i got a rolling garment bag from Briggs and Riley that was amazing, and after over 60 flights still looks new, and will likely last for decades. Best part was that it fit in the over head bin, win!