The main reason and interval for regularly inspecting a beehive changes during the year.
During the Swarming Season; i.e. from September to December.
To determine whether preventive steps need to be undertaken to prevent swarming the hive should be inspected every seven to nine days. This interval provides sufficient time to act if the bees have started building queen cells since the previous inspection.
During the Rest of the Season; i.e. from January to March/April.
Depending on the success of foraging activity, a three to four week inspection cycle should be sufficient to ensure that all is well in the hive. Should you encounter a strong honey flow, you may have to increase the frequency of inspection and take some honey off to provide new storage space.
During Off Season; i.e. from April/May to August.
Provided the bees have sufficient food stores for winter in the hive, the bees should not be disturbed during this time. Opening the hive during the cold season and inspecting frames for food is definitely not an option. Instead, simply lift the hive on one end for a weight check.
An 8-frame single box hive should contain a total of 5 frames of honey; with an average of 2.4 kg per frame this totals to 12 kg of honey. To be winter-ready a single box 8-frame hive should weigh approximately 25-30kg.