QPR host West Brom in the third round of the FA Cup tomorrow and Redknapp will give the competition the respect he feels it deserves.
"I often wonder why clubs in the middle of the table put weakened teams out," he said. "The only chance you've got of winning something in this country unless you're one of the big four or five is the FA or Capital One cup.
"I don't know why clubs don't have a go for it. Going to Wembley is fantastic. Winning's a good habit to get into. I thought we could have taken something out of our recent game against West Brom.