Sometimes I do the same thing, I look for games that I know will definitely win and I double or multi it with other games.
Say Spurs to win is paying 1.09, to me it's another 9% return on my investment so I just multi it with other bets. This is what professional gamblers do to beat the house and take back the commission. There is a lot of tips and tricks out there so just have an open mind.
To stay on topic I sometimes bet a week in advance just to get good odds, there is no right or wrong in gambling. Just winning and losing.