We want to replace our side fence with something higher and more attractive. But we have a rental property next door that’s not in great shape so we imagine the landlord isn’t going to want to invest in a new fence, or will want the cheapest option. If we are willing to just wear the full cost of replacing the fence, is it OK just to go ahead and do it? Of course we will let them know but want to choose something that looks good.
Definitely talk to them first. You never know, they might be happy to go halves in whatever you prefer. They might be planning to sell in the near future and see it as an investment. Whatever you do you are going to need to consult them.
I tend to agree with @Shane. Not consulting them might just lead to further headaches down the line. Worst case scenario, they don't offer any money towards it and you're no worse off than if you'd not consulted them and gone it alone.
Another fence question. Can you put a gate in your back fence? We don't have neighbours at the back - the property backs onto parkland. It would be good to have easier access than walking around the block.
I often see gates on properties backing onto parks. I would just check with the council first but doubt it would be a problem as long as it is locked.