Actually there are two things to remember about Tajweed and Reading Quran with Tajweed,
1) Reading the Holy Quran ins obligatory upon every muslim. It is called Fard Aien.
2) Learning Tajweed as subject is communal obligation. As if no one from a community learn or have knowledge of Tajweed, the whole community will be sinful.
Thats why we should at least learn the Holy Quran with Tajweed and must know a little of Tajweed.