The biggest employers of a hotel are the housekeeping department and the food service department. A worker could be employed by the hotel as an apprentice in the kitchen but after a few years with hard work and perseverance could find themselves as a Chef de Partie, running a section of the kitchen, or even a Head Chef in charge of the complete service of food and drink to the guests.
Any building that is used by the public has to be fit for the purpose, and this includes hotels which have Health and Safety Regulations that they need to adhere to. These regulations tend to come in a form of standards which should be found displayed in the hotel in full view of the public. To keep these standards at an good level then the hotel will need to employ a large variety of support staff; electricians, builders, carpet fitters and plumbers might be amongst the staff. Some smaller hotels, who cannot afford to keep these workers employed all the time, will contract out certain jobs, employing staff from outside of the hotel to complete essential maintenance work.
The quality and quantity of staff employed by each hotel will not only depend on the size and capacity of the hotel but also the prices charged. You would expect first class service if you were paying a high price and would expect all of your needs to be catered for when and where you required. Some hotels will have 24 hour room service and employ concierges, who will pamper to their guests every request. Other hotels will stop breakfast service at 9am and not serve lunch until 12pm. It all depends on how much a guest is willing to pay and/or what the hotel can feasibly provide.