the more blogs you have the more advertising you have to do and the more posts you have to make and so on and so... no. i have to say looking back i wish i had only made one blog for everything. changing everything now is way too much work and it keeps me from doing new posts and new projects. and the spam is overwhelming. the more sites you join the more newsletters and emails you get. just say no to other blogs and link your stuff to one main blog. its easy to categorize or label your work so you can have many different interests in the same space and yet your readers wont have to wait weeks or months to hear from you and they will be less likely to lose interest. so doing only one blog is good for business too.
also, the nightmare of pasting ads and tracking revenue is lessened by having less blogs to watch. and less stress means more posts which means more readers and more money. monetizing multiple blogs can work but if all your readers are coming to the same place, then you get more eyes on your posts and more readers. think about it. if you have to do ten posts a week about ten different topics then you will be stressing yourself out for nothing. sure you can just do one post in each blog per month but then you are splitting up your fans and your time. and time is definitely money.
and really how long you gonna live anyway?