I use a silk cap and a silk pillowcase (because one can never overdo it, haha), and yep, second day hair every time. The silk seems to not only prevent frizz, but also reduces any leftover from the previous day. I always have less frizz in the morning.
As a decent alternative, the Stay-on Satin bonnets you can get at Walmart aren't bad. Not as good as silk, but they're cheaper. If you want a really nice silk bonnet, Blensblend has them in different lengths and the silk is very good quality. Pretty Antoinett's also has nice bonnets.
Former longhair, now CG, living in N. California where the fog meets the wind
3a/b, fine, normal porosity/elasticity, high density
Conditioner wash and style, sometimes with a dab of BRHG.