what should one consider when looking for a travel companion?

im single and not attrached and considering weather to seek a travel campanion. im trying to think of all the benefits and pit falls. has anyone had a bad experience that i may learn from.
should one share the cost equally.

you should look for someone first of all that you know, then it also must be someone that you get along with quite well. you should also have the same likes and dislikes as your travelling companion. considering you are going to spend quite some time with this person doing all sorts of things ( touring, dining, sightseeing and sharing a room). Bottom line is pick someone you know who will enjoy sharing the opportunity to see new things and have a good time and bring back some fantastic memories.

COMPATABILITY
Travel means different things to different people.
It is vital that you are on the same page as to what you want from your travels or you are doomed. Well, not doomed really-you'll just end up going your separate ways during the trip.

Like minds travel together best. If you're a partier, you don't want to travel with someone who prefers to be in bed by 9. likewise, if you're adventurous, you don't want a "rabbit", if you like the mountains, you don't want to travel with a beach person. So in selecting a companion, choose someone who likes to do what you likes to do.

As for sharing the cost, unless you are in a position to invite your companion to travel with you, all expenses paid, they should realize that they'll need some money to contribute. You may want to pick up the cost of the hotel, and let them cover their air/travel cost. Example, recently traveled with a family member who paid for hotel for first leg of our trip, so instead of splitting the cost, I picked up the ground transportation costs (taxi to/from hotel, cabs/bus around town). But, no way should they expect you to foot the bill for their meals and incidentals.