The reasons for the longer term leases could be because of many reasons such as fitting out, informing their business partners, notifying suppliers of the change of business address, updating business directories, re-printing business cards, updating online directories, reflecting the new address on company website, redoing marketing collaterals, migrating of servers etc
Frequent change in business address can also mean disruption for employees who may find the next office or warehouse location inconvenient when commuting from their home to work.