New to yeast starters

So I'm trying to start to focus on the yeast and fermentation temps more now. My question is, for a yeast starter, do you only do it with yeast from a previous batch, or are they still worth doing with wyeast smack packs and dry yeast. I usually get bubbles in a day or two, but I don't want to try washing and reusing yeast yet...so is it worthwhile to do yeast starters with pre-packaged dry and/or liquid yeast? Thanks!

I think that a high gravity beer needs a lot of yeast. I use a smack pack for OG up to about 1.045. Anything higher than that and I still tend to use a starter. I hope to see signs of a krausen forming within 4-8 hours when using a glass carboy. In my plastic fermentor I usually see really active bubbles in the air lock after 24 hours.

Simple answer is yes.

Many different routes you can go.. But generally every brew I do uses a starter.
My first 2 batches never used starters. I simply followed the directions of the smack pack or the vial.

Different options depending on time, space, and money:

1. Smack Pack or Vial to a 1-2L starter and start it about 3-4 days before your brew day. Once your brew day arrives you can dump all of the starter into your beer. (you can also chill the starter for 24hrs and decant most of the spent starter.)

2. Smack Pack or Vial to a 1-2L starter as above. Except you leave just a tiny bit (maybe 1/3 a cup) in jar/flask you are using, and put in new / fresh wort to grow-harvest even more yeast for a future brew. (lots of instructions in the forums about storing yeast.)

3. Same as above excel you make a Larger starter at the beginning and simply "wash" the extra starter/yeast and save that for a future brew.

Lots of different options from here.

I personally use to do #3, and have about 10 quart jars filled with 5 different strains I like to use. But those 10 jars are quickly taking up alot of valuable room in my freezer.
Now I use a different method, where I save my original starter vial or smack pack and use 1/3 of it to make a starter.

So, if I'm not really concerned about saving yeast from prior batches (I'm still trying to perfect other aspects before I worry about that), making yeast starters with what I buy from my LHBS is still worthwhile seems to be what I'm getting from this

Yes, especially if you are making beers with a higher starting gravity.

My favorite part to using a starter is knowing that my beer will start fermenting usually in 4-10 hours depending on my starting gravity. The hef I just brewed start bubbling the airlock in 4.5 hours. (I went to lunch with friends and left it in my beer room at ~74F) Normally it goes in the fermentation chamber where it sits at a chill 66F.