It is up to you to calculate if it is interesting to bet on the same prize over several days (by comparing the prize window and the Sweepstake)
For example for the DVD Arthur and the Revenge of Maltazard, 83'107mp in Sweepstake, 921'100 in the prize window. If we spend 11 tickets at 83'107 we get to 914'177mp, so up to 11 tickets we win! and this is the same for all Prizes (I calculated).
The more you bet, the more chance you have of winning the prize but the less interesting the "win" will be... to see.
yes it's quite that!!we should bet only once, because if you do more than one we're not refunding any of the Sweepstakes we bet on the prize win!!but we can bet several times but not more than 2 because after that depends we're not winning on the prize