How often do you use the blending tool in Illustrator?

Hi Mohammed Magdeldeen, Thank you for Inviting Me to Answer your Question.
I use CorelDRAW Graphics Suite often.
Once in a Blue Moon I use Adobe Illustrator depending upon the Circumstances.
I personally feel CorelDRAW is more User Friendly than Adobe Illustrator.

Not very often.
Maybe once every 10 projects.
It's too specific a tool for me to use too often.

If you are using Illustrator for detailed imagery creation, the Blend Tool can be your most important tool.
Compared to the Gradient Mesh Tool, the Blend Tool is a Live tool, meaning that you can change its object or shape, its color or position, and the blend will be updated live.
You can create blends either with the Blend Tool or the Make Blend command.
One thing to remember though, the Blend Tool takes a lot of RAM, so it may slow down your computer.