How to solve Macbook slowdown and spinning beach ball issue

Question

I've only had my Macbook Pro for one year so far, so it's JUST outside of warranty by about a month. Over the last few months or so, I've noticed it start to lag when opening applications or loading files. Sometimes webpages will cause a spinning beach ball which will then take around a minute or two before it kicks into life again.
I'm wondering if there's any reason for this or what I can do to clear up the issue? I've still got over half the amount of hard disk space available on my laptop, so I'm assuming it's not to do with that, and I can't see anything in activity monitor that stands out as being a true culprit of this. Is it just typical slowdown caused by having a lot of programs installed over time?
I usually find it happens more when I'm trying to load another program or do simultaneous projects at once. However, although I only occasionally turn off my laptop fully (it's usually in standby for most of the time) I find initial startup time when loading the laptop up takes longer than it should when it's logged in to settle down. I'm guessing this could be the number of things I have on startup but I'm not sure if there's anything I could remove that would speed up the issue.
Any advice you could give would be appreciated. Thanks!

Answer 1

When you have the problem, note the exact time: hour, minute, second.  
These instructions must be carried out as an administrator. If you have only one user account, you are the administrator.
Launch the Console application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Console in the icon grid.
The title of the Console window should be All Messages. If it isn't, select
          SYSTEM LOG QUERIES ▹ All Messages
from the log list on the left. If you don't see that list, select
          View ▹ Show Log List
from the menu bar at the top of the screen.
Each message in the log begins with the date and time when it was entered. Scroll back to the time you noted above.
Select the messages entered from then until the end of the episode, or until they start to repeat, whichever comes first.
Copy the messages to the Clipboard by pressing the key combination command-C. Paste into a reply to this message by pressing command-V.
The log contains a vast amount of information, almost all of it useless for solving any particular problem. When posting a log extract, be selective. A few dozen lines are almost always more than enough.
Please don't indiscriminately dump thousands of lines from the log into this discussion.
Please don't post screenshots of log messages—post the text.
Some private information, such as your name, may appear in the log. Anonymize before posting.