The 29-year-old flanker told The Waikato Times: "It's not so much that I changed my mind a lot, but it's probably the last contract that I'll sign as a player and you want to be pretty thorough and know that whatever decision you make you can live with that.
"Once you're out of the game you're a long time retired and you want to be happy in your last few years, I guess."
Gibbes will start at lock for Waikato against Taranaki in New Plymouth for the first pre-season game of the year.
He is keen to play in the match after returning to full fitness from recent hamstring problems, but admitted: "I'm a little underdone and probably not as well conditioned as I'd like to be.
"But to be fair it's been going on two years that I've been playing most of my rugby feeling like that, so I'll just get on with it."