Any Scottish secondary teachers, re study guides

[PJ67]

I have loads of cfe study guides/how to pass/past paper books etc for national 5 and higher subjects that ds1 has finished with. I have two other sons who will start national 5's in a couple of years. Are these worth keeping now that there are second editions out (holder Gibson and leckie and leckie) or will the basic content still be relevant? I'm thinking maths, physics etc can't change much but maybe the curriculum changes. Thanks