Going to put new skirting board in my house but which is best MDF or softwood
On the whole, MDF, as it doesn’t shrink over time, or weep. The only downside with it is that it can be hard to get in lengths over 8’. If you’ve got a decent mitre saw and know how to use it though, joining can be done invisibly.
Hi mac… scaniason is spot on.
MDF is far tougher than softwood, and much more resistant to gouges and dents/bruises. Obviously only suitable for a painted finish, and needs priming properly to ensure good adhesion of u/coat and topcoat layers. As said, it doesnt shrink or expand, so well-cut mitres/scribes stay that way with no filling or maintenance needed. If you have a good, sound wall surface, you can get good fixing results with tube adhesives (no nails etc.) applied with a skeleton gun (mastic gun). Just peg the lengths firmly back to the wall for a few hours ( usually favourite to brace from the opposite wall) and you dont have any drilling, plugging, screwing or filling to ■■■■ about with. You can also join lengths using the biscuiting technique, but thats more for the real pros with the serious kit. Avoid the lightweight B&Q type outlets. Source from a serious merchant and you shouldnt have any problem with getting any lengths you want. When i was in the joinery game, we used to get 5-6 metre lengths on site regularly. Available in many different profiles and sizes, it scores in so many ways over softwood skirting. 
Thank you for all that information, i’m not at work Thursday so going round the builders merchant. I am going to paint it so MDF sounds ok glad it comes in long lengths as i have 3 walls over 5metres long and don’t want to join two pieces.