I have less patience! :)

Once it starts looking like this, roots will emerge days after.

What method are you using to root them??? The best thing is to not disturb the cutting right now. Especially if you have it potted in a cup. Pulling it out to check for roots will break off the fragile small roots if there are any.

I am using 7deuce system. Thank for replies.

A bit too early to start checking, try in about 14 days. 

Frank, if I wrap in newspaper like that, my cutting desintegrates.... why is that? how hot you keep them?

Be patient grasshopper. Some of my cuttings are just beginning to show roots/bud swelling after 10 weeks!

Even with the best conditions, some cuttings take many weeks to root. I suggest you try a few with a non powdered rooting hormone such as Dyna Gro which is a gel. That usually speeds things up for me. Others recommend Dip and Grow

Finally some cuttings started to root. I doubt that the thickness of skins can affect different rooting time in the same soil and the same temperature.

There is so many variables that determine rooting times.
How fresh the cuttings are,
The variety as some are just basically harder to root.
Temperature.
Moisture.
Rooting medium.
What time of year they were taken.
Some cuttings taken from the same tree but different branches root better than others.
Most of all is luck!
I never heard anything about the thickness of the skins (bark) but I'm sure that would play a part to. Once you get the hang of it you'll find that your odds get better and better.

Mine take a month on average. I use nothing on them. Cleaned, bleached, ends waxed, sphagnum baggie, ambient room temp. Works for me.