You at least need 6 months guaranteed rates. Some callables the call schedules are once every 3 months AFTER the first 6 months. Those even at 0.1 - 0.2% lower rates, still far better than callable that can be called just one month after purchase. The worst scenario is, you have a ONE MONTH instrument which is 5.8% APY versus other instruments that might be 4.8%+. The difference is 1% for a Whole year.
So for a principal of $10K, the difference in the interest earning is $10000 x 1% /12 = $8.33 per month.
Who cares for that peanut extra?
