should I get rid of my strawberry plants and get fresh this year or would mine be alright for another year, mine are currently started there 3rd year.
As you've got them, I'd let them grow this year and take runners at the end of the season.
You could buy some young plants in Spring, then you've got them at different ages.
The recommended cycle for Strawberries is three years, first year remove flowers and let the plants build a good root, second year fruit, third year fruit, fourth year compost. As an old gardener I know this to be just a guide. Starting my plants back into life at the end of March (NE England) by cleaning the tops removing any broken or old stalks and repotting putting some of the more advanced ones in the greenhouse for an early crop. They are all in pots so I can move them around and keep the snails off them, lifting them onto tables or on top of other pots that way I can turn them daily.
I let the first year fruit, the second year are up to speed and third year always seem tastier do'nt ask me why. I take the runners into pots as soon as they show and last year some fruited in September, they do not look any the worse for it. Fourth year I put aside take any runners then compost them although if they fruit I let them do that first. We gardeners do our own thing after years of experience we live and learn in fact never stop learning. Let your plants flower and fruit it could be your best crop yet.
I'd say if you want fruit from a plant, don't let it make any runners till after it's fruited, or you'll get fewer fruits, and smaller. You only need one or two new plants from each anyway which you can get in September.
Unless you've got disease (they're prone to viruses) or you want a different variety you should be able to keep the cycle going for years, but I'd certainly agree that four years per plant is plenty.
Presumably you can, perhaps next year, replace half, and then the following year do the same. That is my intention. I was surprised at how well runners planted in the autumn did compared to new plants bought the following spring, and will this year probably plant some runners for the next year.
I just let mine keep going - and they seem to carry on! Four years on and the last crop was the largest and tastiest yet. Mine are in a large raised trough. They do tend to run and develop new ones as well.
For what it's worth my strawberries are left au naturel. They are still going strong after 6 years, fruiting well, laying down new runners and doing things their way.
Should I be closhing them or leaving them under netting?
Only compost them when their fruiting drops right off and always propagate some runners as insurance. If you end up with too many give some to the local school for their Summer fayre plant stall or a friend or neighbour. If grown in pots refresh the compost annually in early Spring incorporating some blood fish and bone into the new mix as Strawberries are hungry plants.