One of the main trademark restrictions is the requirement that the trademark is put in use 5 years after registration. In some countries a 3 years period may apply. If you do not use the trademark for the products or services for which you have registered the trademark, third parties can file an application for revocation.
Preparations for a new product or new service can take a lot of time, sometimes more than 5 years. If the trademark still has to be protected but the use requirements will be applicable in the near future, refiling the trademark is seen as a solution to get a new 5-year term.
However, the EUIPO has become more strict with these refilings. Just refiling the trademark for the exact same specification might be seen as occupying a trademark (and thus an act of bad faith): this would create an infinite monopoly. If however, the refiling is done in the normal course of trade, for example for a broader specification and there is proof of the preparation and the bona fide intention to use the trademark, a refiling could stand.
This matter was recently discussed in an invalidation action filed by a Croatian company against the brand MONOPOLY of Hasbro. Hasbro acts against -OPOLY trademarks and bases its claims on recent registrations. The counterparty found this to be dishonest and stated that Hasbro just tried to avoid the use requirements. The EUIPO does not share this opinion and is states that the handling of Hasbro is not per se an indication of improperly and fraudulently extending the use requirements term.