What Should I Consider When Planning a Modular Kitchen Interior?

I am planning to redesign my kitchen and want practical advice before finalizing the design. I want the space to look modern but also be easy to use every day.

For a modular kitchen interior, what things should I consider first? I am particularly interested in storage planning, cabinet materials, countertop options, hardware quality, and choosing the right kitchen layout for the available space.

I would also like to know whether it is better to go with a ready-made modular setup or choose a customized design based on the room size and family requirements.

If anyone has recently planned a modular kitchen, I would appreciate hearing about your experience and any mistakes you'd avoid or things you would recommend.