The most important advice is to replace them! I never really thought about it until I was watching an alterations video and she laughed about how old her mother's seam ripper was. The next day I bought a new one and OMG - it was unbelievable! Just one of those silly things (like replacing your needle more often) that we forget to do and it makes things so much easier. I buy a fairly cheap one (prefer the longer ones) and just replace it when it gets 'well-used'.