Here are some situations in which you should use a tree pruning service.
Some branches seem much healthier than others
If you've noticed an imbalance in the health of your tree (meaning that some of its branches and leaves appear to be thriving, whilst others look unhealthy), then you might need to have that tree pruned. Sometimes, this problem is the result of the healthier branches acting as a barrier between the sunlight and the other branches.
You might, for example, notice that the tree's longest outer branches, which receive the most sunlight, are doing very well and the shorter ones that are closer to the tree trunk have fewer leaves and generally look less healthy. This could be because those longer branches are preventing the shorter ones from getting enough light to allow photosynthesis to occur. In this situation, pruning back the thriving outer branches that are preventing the light from reaching the inner branches could allow the latter to become healthier, which could, in turn, fix the half-healthy, half-unhealthy appearance of the tree.
It's especially important to use a pruning service if it's a fruit tree whose fruit you like to make use of. If a large percentage of the branches are unhealthy, they may either bear no fruit, or the fruit it bears might be low quality and inedible.
A few small branches seem to be diseased
If you've noticed that one or two small branches look like they might be diseased, then it would be sensible to have a tree pruning specialist prune these branches. More often than not, a tree that has become diseased will eventually die. However, there are instances in which it is possible to keep a tree alive if the disease has only recently developed and is only affecting a few of its branches.
In this situation, having the branches pruned before the pathogens on or inside them spread to the trunk and other branches could stop the disease from taking hold and destroying the entire tree. However, if you suspect this might what's happening to the branches, you must get the pruning done immediately, as the pathogens could start travelling around the other areas of the tree within days of your discovery, by which time pruning the visibly damaged branches would be a waste of time.
For more information about having your trees pruned, contact a local pruning service or arborist.