Adam Kritzer, en un post en Forex Blog, plantea muy bien los diferentes horizontes temporales que manejan los inversores y los traders (en este caso de moneda), haciendo foco en el Euro.
But seriously, currency traders must adapt to the zero-sum nature of forex markets by shortening their time horizon. Stock market investors, on the other hand, are not bound by this constraint. In fact, by holding stocks for a long enough time period, investors can actually turn this into an advantage.
Simply, currencies fluctuate. Since its introduction 10 years ago, the Euro has fallen, then risen, then fallen, then risen, then fallen again to its current level. If you initially invested in Europe 2 years ago, the exchange rate would erode your returns if you tried to sell now. If you invested 5 years ago, you would break even. If you invested 10 years ago, you would come out ahead. In the end, it’s only a question of perspective. Still, if you maintain your positions for long enough, either you will break-even from the exchange rate or it will only marginally affect your returns (on an annualized basis).
In short, unless you deliberately want to speculate on exchange rates, don’t worry about them! If your investing horizon is long enough, their fluctuations will neither help nor hurt you in a meaningful way.