How often does your oil tank get filled?

In the winter once a month.
In the summer...we usually go for about 4 months or so.

Ours is 275 gal as well and gets filled approx once a month in the winter. Nov/Dec - April, last summer we used the hot water heater for hot water and we shut the boiler down and only got one delivery to top it off.
But this year I imagine it'll be the same as cooky....

ETA: though after this freezing cold weekend they will probably be here to fill it again on Monday

we do also once a month, maybe a little more now because it is so cold.
Ours is about 250 gallons.