Why Boring Repetition?
If you want to minimize studying time, repetition is important. If you repeat, you tell your brain this is important, remember this.
Repetition should be made at certain intervals of time. Of course it's best if you experiment and find your own optimal intervals but a general guideline is as follows: After one hour of study wait ten minutes. During these ten minutes your brain will organize the new information. Then you should briefly repeat the information during about five minutes. The next repetition should be after about an hour, also about five minutes long. Then repeat again after one day, as much as you feel needed. Try again after a week and then after a month. Hopefully the information is in your long-term memory by then.
Note that these are only general guidelines which may very well vary due to the nature of the material you study, your studying technique, etc. Experiment!
There already exist several software programs that optimise the repetition cycle. Most of them use the Leitner system approach.
The best combination between using a structured approach and optimal repetition intervals is realised with RecallPlus(proprietary). RecallPlus uses concept maps for structuring the learing material and then uses repetition cycles, associated with the links between topics.