Keep an eye on your weight and work on making sure you are not gaining extra lbs.
Even if you gain just a pound or two every year, the extra weight adds up quickly.
That said, if you are trying to lose weight, do not weigh yourself obsessively. Once a week tops.
The reason I suggest once a week at most is because your natural body weight can fluctuate up to 7lbs from morning to night, from one day to the next!
Therefore, to get an accurate measure of your weight, weight yourself once a week, at the same time of day, on the same day of the week, on the same set of scales, wearing the same or similar clothing.
Again, if you are actively trying to reduce your weight, by moderating your eating or increasing your activity levels, I would also recommend taking measurements of your body.
Some people find the numbers on the scales come down first, some people lose inches off their body first.
It's an individual thing.