People will tell you that you should build a portfolio to attract clients. Or they'll tell you not to waste time on a portfolio. Focus on relationship building instead. But my reason for keeping a record of my writing work? To look back on it when I feel stuck. To remind myself that I'm actually pretty dang good at what I do. So even if it's just snagging a screenshot of your latest deliverable, do it. Save it somewhere. Keep it for those days when you feel "meh" about it all.