for every how many months I need to change my baby's silicone spoon

A. no need to change if it's visibly ok . also you can use steel ones slowly .  Give khichdi, daliya, upma, curd rice all in mashed form. add veggies, give fruit purees. better to give more fruits, veggies ,instead of sweets  as children don't have much likes and dislikes at this age. so they accept variety of flavors.