Sealing your hair weft is something that can help to extend the life of your weave; however, this is a process that is not required to be completed. It is one that is certainly useful for weaves that are more curly and/or wavy in nature. You place more pressure on the stitching of your curly and/or wavy weave as you run your fingers through your hair as opposed to natural wave and straight hair.
The aforementioned tips are also useful for curly and/or wavy hair. Again, weft sealing is something that makes sense for both of these styles, but it is a process that is not required to be completed.