Why is the room looking so tired already?

[Blib]

Hi all, first post!
So I decorated a small bedroom about 2 and a half years ago and spent lots of effort preparing the walls before decorating. I noticed in good light today that all the lining paper seams are visible, there are cracks around the coving edges and generally it looks tired and need of a coat of paint if not a strip back and re-do. I don't mean scuffs to the walls etc as that is expected, its more that the fabric of the room is degrading/ageing. I would like decorating jobs to see out 10 years if possible so what can I do better? I am a DIYer who is willing to put in prep effort and spend a bit more up front so any feedback for future projects is massively welcome.

About this particular room:
its roughly 2.5m x 2.5 meters, south facing with a large window and is the master bedroom so two adults sleep in there. Originally I stripped back, filled, rubbed down the walls and ceiling. I put up coving all around and then lined the walls and ceiling. I caulked all the edges and put two coats of white ceiling paint on the coving and celing and some natural dulux paint on the walls.
I buy everything from Screwfix (so paper, coving, paste etc) except things like paint.

-B

 

[JP_]

photos?

 

[Blib]

Good idea, bit grainy unfortunately but here they are. Is this poor wallpapering on my part? It looked seamless when I first did it but it has not aged well!
Serious thought - would a skim be better for longevity? I've no problem learning how to do that if this is typical for lining.
Its possible that the walls didn't need lining but I wanted to smooth out any minor undulations.

-B

 

[sxturbo]

the cracks are movement, its likely they will come and go throughout the year. you can try digging the cracks out a bit and fill them with flexible filler.

The lining paper seams, i think its a thing with lining paper, i'm very good at papering (blowing own trumpet i know) any patterned paper always seem to be ok, but lining paper its ok when first hung, but then once its painted get some lifting at the seams drives me crazy. that being said i have read somewhere that when lining the room, the seems should be filled and sanded down.