I hope it is not off-topic here, as it is mean to increase uptime without lags - using swap on microSD (even class 2) and re-enabling it after total amount of data written to swap partition exceeds 600 (*not* data currently on swap, but data written totally, check iostat), result in absolutely 0 negative effects of long uptime.
Using the above (re-swapping by semi-automatic script that I've based on shadowjk's work) I used to get uptimes like 30 days (sic!) without any negative effect on performance (used, because now I'm installing/tweaking etc. things, that many times require reboot to take effect).