I made my first currency trade in October 1973. After Bretton Woods, spot settlement rules were still in their infancy. At that time you had a choice of forward swaps, such as 30 days, 60 days, etc which could only be realised at expiry. At Ross Perot's Dupont Glore Forgan office in Toronto arbitraging between 30-60 and 60-90 day swap spreads was a popular strategy. After 30 days your swaps mutated to spot-30 and 30-60. If an expiry fell on a weekend and the invariably mean-reverting arbitrage happened to be in your favour, you could either earn settlement interest or roll the swap positions forward. It was a win win - now or later - situation.
That was two years after the gold standard had been abandoned - causing the big inflation of the 1970s - and one year after the creation of currency futures contracts at the IMM in Chicago. I am still in touch with Mark J. Powers, the father of currency futures (together with Leo Melamed). Mark allocated pension fund money to us in 1990. In their due diligence, he and his partner Mike Dubin put emphasis on knowing the manager personally by asking him tricky questions over an extended lunch. I was impressed by this pleasant approach.