I finally purchased my first bowling ball last week. I highly recommend that any person who enjoys bowling purchase a ball. The difference between a house ball and one that is fitted to your hand is worth the price.
I participate in a men's league as an alternate. I bowl about once a month, and I've consistently bowled between 115 and 140. I could usually count on picking up a few strikes and a few spares. There were some nights when I was very good at picking up spares, and others when it was difficult. That was with the house balls.
I never considered myself invested enough in bowling to buy a ball. Compared to other sports equipment, they aren't terribly expensive. I was able to pick up a ball and a bag for less than $200 at a local pro shop. On the recommendation of my team mates I had my ball drilled for a fingertip grip or hook grip. Before that I used to throw a straight ball with a very slight hook.
It didn't take me long to adjust to the hook. I read somewhere that bowling a hook is a similar motion to throwing a football underhand and then answering the phone as a follow through. I worked on throwing the football and answering the phone.
It took a couple of games for me to adjust to the new ball and the new style of bowling. I think I bowled a 136 and a 121, which were pretty normal for me. I was getting more strikes than I normally did though. I had six strikes in two games. The biggest problem I had was open frames though. I couldn't pick them up with the hook. In the third game I had the football telephone movement down pretty well. I threw about 6 strikes in the third game. The big difference in the games though came from picking up my spares. I found I could throw a very accurate straight ball with the new ball. By throwing a straight ball for my pick ups I only left a single open frame when I failed to pick up a split.
I bowled the best game of my life with a 187. That was nice, but the real prize from that is the sense of control I felt with that ball. It does what I want it to. I never got that feeling with house balls. I'd try to use them consistently, but a good degree of chance would come into play. I think most of it had to do with the way my fingers gripped the ball. The holes didn't fit my fingers well. My fingers usually would get sore and my third game was consistently my worst game. The ball would hook and fade wildly. It really made bowling feel like a gamble.
I don't feel that way with the fitted ball.
This is actually the second time I've bowled with a fitted ball. The first time was when I was younger. I had a hand me down ball we had drilled to my hand. I played in a summer league as a kid. I wasn't great, but I did learn how to consistently release a straight ball that would strike. Back then I felt like chance played little to do with how I was bowling, most of the variance came from fatigue. It's nice to get back to that state of control.