Starter getting weak?

Have a 1998 Venture with 150,000 miles. Recently the thing has been starting hard. Like the starter having a difficult time turning the engine over. When it wouldn't crank at all one day I replaced the 6 year old battery. Seemed to fix it. But days later it did it again. And now the starter is starting to sound weak. Like it's running at about half speed and gives a straining kind of sound. Checked all the electrical connections and they are tight. So does it simply sound like I need a new starter? They are quite expensive but extremely easy to replace. Thanks in advance for any help.

Older starters can 'drag' when the bearings start to wear and get sloppy. The armature can make contact with the inside of the starter housing, causing lots of drag, just like the symptoms you describe.

IMO its time for a new/rebuilt starter.

Unlike older style starters, these are smaller, high speed, low torque motors. Older style starters were high torque, low speed, direct coupled motors. These starters can certainly 'drag' when they wear. http://cemrweb.cemr.wvu.edu/~mathews/venture/armaturea.jpg There are gears that may be worn, or dry and dragging.

Thanks for the replies. It's still cranking but very slow at times. I'll be getting under it in a a few days and reply with my findings. It's starting to show symptoms of a dirty throttle body now as well.