Height of central pole:
2m high for diameter 3m tent, 2.5m high for diameter 4m tent, 3m high for diameter 5m tent. The central pole has a ring that you can hang the light.

It is all a personal choice what size you go for, but as a general rule:
If regularly accommodate 1 or 2 twin size mattress, a 3 meter is fine. (Please kindly note 3 meter tent cannot accommodate double size mattress)
If regularly sleeping 2~3 people, and occasionally four, a 4 meter will be fine.
If regularly sleeping 4+ people, or if you are planning on going on extended week long camping trips where set up time/carry weight is not such an issue, a 5 meter is better suited as it gives you that extra room.
If regularly sleeping 4 people, both 4 meter and 5 meter are fine. However, on balance a 5 meter may be better suited as I would suggest that having slightly more space than you need is not a bad situation to be in.

Windproof grade: the tent can be against 6 degree wind i.e. 30 miles/hours. It is not advisable to use the tent if the windstorm is heavier than 6 degrees.

Maintenance: keep the tent clean and in bone-dry conditions when store it.

Lifespan:
The lifespan of your bell tent is very dependent upon the camping conditions and the way you look after. Air pollution, ultraviolet radiation, natural and domestic dirt, all limit the lifespan of your bell tent. In short, if you look after your tent it will look after you for many years of camping.

After-sale service:
We provide after-sale service for all of the products. If your tent has a manufacturing defect or is damaged in transit, please take pictures and contact us via email, so we can sort it swiftly.