With proper circuit wiring know-how and some DIY building skills, some homeowners can correctly install new bathroom extractor fans on their own. We can unfortunately say that a fair chunk of in-line fans are installed particularly well. If you're unsure, hire an electrician or ventilation specialist. Again there are caveats and nuances which is why our clients just end up going for the low risk option and contracting us in to carry out the project.
Nobody wakes up one day and says, "I need extra ventilation", without good reason. Ventilation systems are usually ordered to solve a problem, or to prevent a problem before it occurs. We can fix condensation throughout a property, poor ventilation and removing bad smells in kitchens and w/cs - we can't fix water ingress, leaks or rising damp with ventilation alone.
In a nutshell, we will recommend and install a system we have a warm fuzzy feeling will put a real noticeable dent in the sort of symptoms you're currently experiencing. The sorts of ventilation systems we fit certainly aren't cheap, but they do produce the results, as many of our past clients have come to find out!