The quick answer is yes - and for every competition you enter!
All competitions should link to a set of rules. No rules doesn't necessarily equate to "don't enter", but they should be there to protect you and the promoter.
Competition rules can help you can check if the competition is running, whether you can enter, how many entries can be made per person/household and any other conditions the promoter has included (for example word limits on tiebreaker competitions).
In the case of competitions where a purchase may be required to enter, a No Purchase Necessary option may be included in the terms. Some competitions may require you to collect a prize whilst others may require some payment in addition to the prize offered (e.g. mobile phone contracts).
