The Ott brand bulbs are expensive but the last about 10 times longer then the other daylight bulbs. I'm still on the original bulb that came with my Ott lamp and it it's over 10 years old. I turn it on and leave it on all day when I'm sewing. When Hancock Fabrics went out of business in my town, I bought all the OTT bulbs on clearance that would fit my lamp. I haven't used one yet.