in touch-based magic, the effects will last as long as you are still touching the person or object, regardless of whether you lose your intention.
i.e. if you pool Happy in your hands and press it into someone, they will continue to feel the effects until you let go. if you alter a dress with touch-based magic, the changes will last as long as you are wearing the dress, etc, even if you forget you used magic.
touch-based magic is intermediate to learn and is best for cosmetic alters, medicine, and intimate partners (or anyone who has license to touch other people for extended periods.)
in speech-based magic, the effects will last until the person or object forgets what you said verbatim.
i.e. if you motivate your friend by saying "you'll do great out there tonight" with magical intent, the effects will last until they misremember your words ("you will do great out there tonight," "you're gonna do great out there," etc.) even if you forget what you said. it is best to stick to simple sentences when using this magic on people for that reason.
speech-based magic is difficult to learn, and best for objects (since objects will never forget something.)
in thought-based magic, the effects will go away as soon as you lose your intention.
i.e. if you think "I need a sword" with magical intent, a sword will form in your hands and this will last until you are no longer thinking about needing a sword. this is tricky to master because thinking about having a sword will still make it disappear.
thought-based magic is the easiest to learn, and best for temporary encouragement and high-stress situations.
in script-based magic, the effects last as long as your writing does.
i.e. if you carve "this table is fireproof" into a table with magical intent, the table will remain fireproof until the writing is obscured, destroyed, or otherwise altered to be unreadable. if you write "I am steve's best friend" with magical intent, you will remain best friends until the words are scribbled out or the paper is destroyed.
script-based magic is nearly impossible to learn and works for most situations.