The Quran and its proper tajweed is a must in every Muslim household. Allah has said in the Quran about tajweed "Or add to it, and recite the Qur'an with measured recitation." (73:4) that is why so much importance is given to tajweed classes for Muslims. Tajweed classes are essential for all ages of Muslims but they are most effective in younger years when the capacity to comprehend and learn is much more accurate. Tajweed classes are given to Muslims with the intention of pronouncing each and every letter and word in the Quran as it is meant to be, the way the Holy Prophet (PBUH) recited it. Hence, tajweed classes cover all the set of rules of letters, vowels and other Arabic words so that they can be read, pronounced and eventually learnt correctly.
The reason tajweed classes are important is because it is the word of Allah and Allah has specifically phrased certain letters and words in a way for them to mean something. Changing the tajweed of those words or letters would mean changing the meaning of what Allah is saying to us and that should not happen. Things like how long the pronunciation of a letter should be stretched is something that can only be learnt by proper tajweed classes. At the end of the day our goal in reciting the Quran should be to replicate it in the same manner as did the Holy Prophet (PBUH). May Allah make us successful , with the help of tajweed classes, to do so.