I’m left handed and have been playing the piano for about two years now and try to do about two and half hours a day. I split my practice into two sessions’ morning and night. Anyway I find that in the second session my fourth finger feels fatigued which becomes annoying when trying to play things evenly etc. The other fingers feel fine and my fourth finger doesn’t hurt it just feels tried. So my question is did other players find this a problem when they started out. My second question is to the more experienced players how many years did it take before you felt that hand strength wasn’t a limiting factor to the way you played.

"Strength" isn't a limiting factor for adults. On day one, you have enough strength in your hands to play the piano. Some endurance is required, but because the strength required is minimal, so is the endurance (if you use proper technique).

Bearing these ideas in mind, my first suggestion would be that there is a technique issue causing your 4th finger fatigue, and not necessarily a strength/endurance issue (especially if you are practicing for 4 hours a day). My second suggestion might be early indicators of potential stress-related injuries (probably due to those technique issues).

Which one is probably impossible to diagnose over the forum, but I hope it gives you a head start..

Anyone has the strength to "play the piano" but the average person does not have enough finger strength to play proper repertoire proficiently, especially if your hands are small. Heck I can reach most 10th and after not practicing for a while I lose the ability to play octaves properly because my fingers start collapsing.

Every serious pianist has fourth finger issues that have to be dealt with - it's just a result of how our hands are built. So the idea is to get it as skilled as you can get it - it's not so much a "strength" thing, I don't think.

Exercises that give it a workout, such as some of the Dohnanyi exercises, are useful. But you must be alert to over-use and forcing things - you want to avoid injury. Doing exercises (mindfully) is one way to build and shape the neural stuff that gets that finger into optimal condition. In my experience, a good deal of issue is about one's perception of the finger and how it works, rather than the actual muscles and tendons, and mindful exercise can refine and expand that perception.

The fourth finger "issue" is usually an independence issue. Hands collapse and fingers try to play together and/or too close together because the proper "spacing" has not been established by any specific physical movement. Almost always technique, and not "strength" (unless you have a physical disability, which is something I'm assuming you'd know about).