I used to bite my nails, but stopped nearly a year ago - I am nearly 60, so a loooong time. I can confidently say I no longer bite them... HOWEVER I am really suffering with vertical splitting. I have had an issue with one nail for many years, but now I have it happening on 3 others - that has only just started. I haven't done anything to damage the nail beds, anyone have any ideas what could be the cause?