Planning a hotel break? Here some things you wish you'd known before – and you'll be glad to know now.

Larger hotels and chains often provide national reservation lines – these don’t have the same power to grant discounts as the hotel does. It’s the same for online booking sites – hotels pay these a commission (up to a third). By calling the hotel directly and quoting the discount you saw, or simply asking for a better rate, you can often get a deal.

If it’s your wedding night, anniversary or birthday, hotels will try to accommodate your special day as best they can. If you’re booking through a third party, don’t expect your request to have made it to the hotel – it’s best to contact them directly.

It makes more financial sense for hotels to offer the best rooms and upgrades to guests who paid more, who booked directly, or who are regulars. These guests are more likely to return and so are more likely to benefit from upgrades.

It’s common in the industry for hotels to overbook rooms. Very occasionally everyone turns up in which case the hotel should – but not always – find you alternative comparable accommodation nearby. Single women, disabled people and families are usually OK, but if you booked a discounted rate, are staying a night, or are rude you’re more likely to be moved.

Corner rooms are generally larger whatever floor they’re on, while top floor rooms are often quieter and have better views, so it’s always worth putting in a request.

Asking for an upgrade when there’s a line of people at the front desk won’t do you any favors – it’s better to enquire when the hotel is quiet, at off-peak times such as midweek, and later in the day. Be specific if possible (“I’d like a sea view”) and always be polite and complimentary without being ingratiating.

Hotels won’t offer better value on rooms in the morning as they have the day to fill them. By late afternoon no-shows are usually known by reception so ask for a room then. Any later, knowing your options are diminishing, hotels may hike the price back up.

There are times when rooms aren’t occupied because they’re in need of maintenance. If you’re stuck you can suggest that you’ll be willing to take such a room – you could get a discounted rate for putting up with any issues.

Hotels don’t want to upset VIPs by letting the world and his wife (i.e. other guests) know that people of note are staying there. So unless you actually see a celeb you’ll be blissfully ignorant that you’re staying under the same roof as a famous person.

Hotel staff can spot them a mile away. They’ve seen it all before, nothing surprises them, and they have no reason to judge you – or tell on you. However, don’t ask a respectable hotel if it has an hourly rate; it’s rude.

Objects such as remote controls, hairdryers and light switches usually get a quick wipe but not a thorough clean which is why research by the University of Houston found that, in some cases, these objects were covered in as much bacteria as toilet seats and sinks.

Fox News reported that maids just tend to rinse glasses and not use washing up detergent, while an anonymous maid interviewed on travel search website Trivago said that in the five-star hotel she works in the glasses, cups and cutlery are sent downstairs to be cleaned but the industrial dishwasher “doesn’t do a great job”.

Most guests presume all linen will be clean, and sheets and towels are, but blankets and bedspreads are washed less often so ask if you’d like fresh ones.

The chances are it will only have been rinsed out with water or it will have been gathering dust for days, if not weeks.

The mini bar is bad for both parties and rarely makes a profit for the hotel despite the overpriced goods. It’s difficult to keep track of what’s been taken, especially if guests only stay a night, so when checking out staff expect a level of confusion and denial.

If you do indulge, check the seals on the bottles first – some sneaky guests have been known to drink the contents and replace it with water. And be aware that bringing your own items can sometimes result in a charge.

These unwanted guests are often unavoidable – if you don’t fancy sharing your bed with pests check out reports on TripAdvisor or other reviews sites before booking, or look at Bedbugs.net, Bedbug Reports, or the Bedbug Registry.

Zeev Sharon, who runs a hotel start-up in the US, told the Independent newspaper that for every $1,000 (£780) spent on a room the hotel charges around $1 (70p) on an average rate. So if you’re staying in a room that’s $300 (£234) a night it will have cost $300,000 (£234,000) to build, decorate and furnish.

This may come as a surprise – you’re paying for the room after all – but housekeeping isn’t there to pick up your dirty underwear and tidy up after you. As they have an allocated time to clean each room the more mess you leave, the less actual cleaning they’ll be able to do.

It may not be in your best interests to go with the concierge’s suggestion but it will be in theirs. That’s because they often get a commission if you go with their advice. However, the places they suggest are usually tourist traps rather than dive bars as they do have a reputation to uphold.

Half-used toiletries are useless to hotels so you’re actually doing them a favor by taking them home, as they’ll only get thrown out. Take pillows, bedspreads or dressing gowns though and you’ll be billed.

Bellboys, doormen, housekeeping, room service and other hotel staff all work hard for little money – tip them and they’re more likely to provide you with extras, including free water bottles, shuttle rides and good reservations. Tipping is especially expected in swankier hotels – if you resent forking out be mindful that in some parts of the world your room probably costs a night what some staff make in a week.

This doesn’t tend to work if you’ve found a hotel via a booking site but if you’ve booked direct and can’t make it don’t cancel – move your booking to a week or two ahead then cancel it a few days later. That way you avoid the 24-hour cancellation fee.

Staying calm is always a good place to start, and complaining in person makes a difference. The front desk is usually the first port of call, but rather than blaming them ask nicely who the best person is to solve your problem (housekeeping, or maintenance, for example). Asking for a name helps, as does a grateful thank you.

Hotels, especially chains, will want your repeat custom and have ways of getting this. Loyalty and membership schemes, free breakfast and Wi-Fi to returning customers, and enticements for booking directly are some of the ruses hotels will use.

Here’s a cheery thought to end on. Staff won’t impart this information, and it’s not something that tends to get asked – after all death is part of life. However, it’s not an uncommon occurrence. Bodies are removed quietly and discreetly then the room is sanitized.