A cruise cabin upgrade can be so magical that cruisers often invoke the "upgrade fairy" when they're hoping to be bumped to a higher-category stateroom. Upgrades come about in a number of ways: surprise complimentary upgrades, upsell offers at discounted rates, re-bookings due to promotional price drops and even online bidding for better rooms (currently only on Norwegian Cruise Line).

But sometimes you should just say no to that upgrade offer.

While that sounds counterintuitive -- who wouldn't want a better room on their cruise -- the truth is that what you think is a better cabin and what the cruise line views as an upgrade for you are not always the same. Here are seven reasons why you should turn down that cruise cabin upgrade -- as well as a few more obvious reasons to say yes.

When to Say No to a Cruise Cabin Upgrade

1 . You're choosy about cabin location.

When offered an upgrade, you usually cannot choose the location of your upgrade room or suite. If you prefer to stay midship on a lower deck to ease seasickness, have purposefully booked rooms near or connecting to travel companions or are picky about decks because you want to minimize noise, you should stick with the cabin you booked and not risk an upgrade.

2 . You need an accessible cabin. Related: 5 Best Cruise Lines for Babies and Toddlers

Cruise ships have limited wheelchair-friendly cabins and very few accessible suites. You can't guarantee that an upgrade would be available in another accessible room, so if you need this type of cabin, book the one you want and say no to potential upgrades.

3 . You only want the upgrade for the perks.

Certain cruise lines (such as Norwegian, Seabourn and Oceania) offer special perks and freebies to passengers booked in their top suites, but don't give all of those extras to travelers who get free or discounted upgrades from lower-tier cabins into the best suites. If you're really in it for the perks, you'll need to book the high-end suites from the beginning; the upgrade fairy will only bring you nicer digs but not all the regular benefits.

4 . You'll lose your perks.

This advice is specific to travelers who spot a price drop on their booked sailing and want to take advantage of the reduced fares to upgrade to a better cabin. Cruise lines will generally let you do this, but they'll consider it a rebooking -- meaning you will lose any promotional offers attached to your original booking and be subject to whatever the current promotion is. For example, if you booked an outside cabin at a certain rate that included a free beverage package and prepaid gratuities, but now see an offer for a balcony cabin at the same price, but the only advertised perk is $50 onboard credit, you can take the upgrade but will forfeit the better freebies of the original promotion.

5 . It costs too much.

When a cruise line offers you an upsell, be sure to compare the new cruise fare (your original plus the upsell price) with the advertised fare for the upgraded cabin. You might find that the upgrade is not that good of a deal, or it will break your vacation budget. Just say no if what you'd pay in total for the better room is not a price you would've considered when you first booked your cruise vacation. Related: 5 Booking Hacks That Will Change the Way You Buy a Cruise

6 . It's not enough of an upgrade.

An upgrade isn't always as dramatic as an inside cabin to a suite. You might get moved from a balcony cabin to a different balcony cabin that has a better location (according to the cruise line -- but not always to you). It's up to you if this kind of move is worth it. We've also heard of upgrades from balcony cabins to Concierge-level veranda staterooms (typically identical rooms with perks of questionable value). This type of upgrade might be fine if it's free and you get the extra amenities, but isn't always worth paying for.

7 . You're worried once you try a suite you can never go back.

This is definitely a first-world problem, but Cruise Critic readers caution that once you enjoy the "suite life," you might never again be satisfied with the standard ocean view or balcony cabin you typically book. If you believe it's better not to know what you're missing, you might want to decline that cruise cabin upgrade.

When to Say Yes to a Cruise Cabin Upgrade

1 . The upgrade is free or reduced-price. Related: 3 Ways to Make the Most of Wave Season Cruise Deals

If you're not picky about location but would enjoy the extra space of higher-category cabin, say yes to that upgrade if it's free or at a reduced price that is still well within your travel budget. You can easily check fares online to see what the new room would cost if you booked it directly and can compare with the upsell offer to assess the value of the offer.

2 . You'll move up to the next cabin type.

More space is almost always worth any minor trade-offs (like being far from the elevator or subject to more noise from surrounding decks). If you can move from an inside to an outside or from a balcony to a suite, for free or for cheap, we say go for it.

3 . You will definitely utilize the extra space.

Are you trying to squeeze four people into an inside cabin, or are traveling with lots of family who plan on hanging out in your room? Have you always wanted a huge suite so you can throw a cocktail party for the friends you made on the Cruise Critic boards? Definitely take that upgrade if your cruise will be enhanced by having the extra space for a higher-category room.

4 . You will get extra perks.