It never ceases to amaze me how often this same question gets asked.
Because the movements in rep watches are used/unserviced, no one can here tell you if/when the movement was last serviced (if ever) or when & how it may break down in the future. Because of this, a good rule of thumb is that if you plan to keep the watch, have it properly overhauled when you receive it. Then, like any mechanical watch - rep or gen - you know you are good for 5-7 years, at which point the watch should be serviced again.
Having said that, alot of people take their chances & wait until the watch breaks down before having it serviced, which is fine for common/current movements, since parts are relatively cheap & plentiful. However, for older watches, where parts may be difficult to find or expensive, you would be wise to keep the watch serviced on a regular basis since parts are much less likely to break down when properly oiled.