K.Y.
I kind of agree with all these responses so far- My twins are 22 1/2 months- I have a boy and a girl-
My boy started this around like 11 months ols, I believe- he started byt crawling up the back of the couch and into the windowsill to stand-, and crawling in and out of drawers- I got great video of this, it was very cute! (His dresser is built into the wall)- then when he started learning to climb out of the crib, we had to trade their cribs as hers was a lower mattress.
I still haven't found a solution, and now she is older, she climbs a little more- she is a little chunkier too, which I am sure why she didn't climb as early. They will now climb OVER the rocker recliner, stand on the upside down laundry basket, etc, but we keep the kitchen and stairs gated off so they can't get too far- (thought they will try to climb the gate sometimes).
they can now also climb up in their highchairs and onto the changing table by themsleves, but this is good for me cause now I am 34 weeks pregnant! Less to pick up! :)
The only thing to do really is keep getting them down and saying no, and be careful about leaving them in a room alone for more than a moment! I do love the sticky tape idea- gonna try that today I think in the windowsills. Good luck!