Maybe its not so much if you should use them: but what kind, how tall, what else needs to be done when using them, and..... then, when should you take them off? or if?
But to answer the specific question... I have a question, or 2 or 3 or 10 - most importantly "how tall are your tubes" and do you have them caged or intend too? Is the tree staked or will it be. Do you have aluminum window screen wrapping the lower section of the trunk or not... are you going to paint the trunk white ... are you in an area where your going to have an adverse greenhouse effect with the tubes (prolonged freeze thaw cycles) and or moisture issues.
I would be looking at pulling the tube for reuse if its a tall tube and the tree has developed a decent sized diameter trunk and is not flimsy but then you have the issues of it just tipping over if its not strong or wind hardened and you pull the tube and leave the tree unstaked .. you can go the route of leaving it in the tube but that has some possible draw backs - Butttttt........ if the tree has survived this long and not had a mice nest and you have not been stung peeking down into them you wont likely have issues just leaving them on till they pop apart (hopefully they break down and pop apart). Tree tubes do not provide long term protection from browsing unless they are super tall which would not be great for fruit trees.
Fruit trees need scaffold branches, they need to be allowed to develop good crotch angles on those branches. What height do you want the lowest ones to be at ... are they dwarfed trees or standards? There are a ton of questions that should be answered... I pretty much can go on and on.
I think it is the complexity of the many possible factors at play that make tube use controversial they are a Awesome/Evil/+/- thing.
I think they are a great tool for quick growth and coupled with window screen are decent for a few years but beyond that without caging they just make for a nice focal point to draw deer into for a tasty snack. So I would pull them and cage the fruit tree if you can afford to, if not, keep them on a bit longer especially if they are shorter tubes.
Right now everything wants to kill your trees - tube or no tube... voles, mice, bugs, deer, deer with antlers and mother nature even some dude on a snowmobile or driving a tractor so you have to protect them. How you apply that protection evolves with time and there are many different opinions out there. If you are, in your gut, questioning it now then Im guessing your tree is ready to move onto the next stage in its life with a differing level/means of protection.
Pull the tube - the tree is out of the tube apart from antler rubs the benefit is over... my 2 cents; and in doing so it eliminates other issues - but protect the trunk and cage it if you can.