Ask a Warrior Thread.

Once you understand how much acc you need to hit what you want to hit 100%(ussualy around 139 for training, 165 for horntail) the base dex you need becomes obvious. Look at the stats of your equips and see how much acc you'll get from them all together(1 dex = .8 acc, 1 luk = .5 acc). Google for an acc calculator and put in your stats + whatever you're training's stats to see your hit rate and acc required to hit 100%. If you need more acc upgrade your equips as much as possible; add dex to your base only as a last resort.

Ussualy it's possible to be dexless at least up until your 80s with ease. Even after it isn't too hard to be dexless with good acc/dex equips.