Conservatories are cleaned on a regular basis along with the windows of the house which is usually every six weeks with the only difference being the roof. This is cleaned on an ad hoc basis. Most people get them cleaned once a year as standard.
You may find your roof will need to be cleaned more regularly depending on the build up of moss and algae. Trees that are in close proximity, traffic dirt, and moss from the roof of your house are all common contributors. Therefore it will depend on your own surroundings as to how often you decide to get it cleaned.
The price to clean a conservatory is generally £30 upwards. I am more than happy to come out and advise you of the cost free of charge prior to a clean, just give me a call. At the same time I will survey the access to ensure I can carry out a complete clean. On occasion it is not unheard of for me to access one side of a conservatory via your neighbours property, so seeking permission prior to me coming is helpful.
If the neighbours aren’t happy to allow access this may cause the conservatory to only be half cleaned, as I won’t be able to get access. This will be advised before hand.