Any small amount of standing water can be damaging to your gutters. It’s recommended that a ¼ inch puddle or more should be addressed. Failure to keep water from pooling in your gutters can result in clogs, algae growth, and pests that damage your gutters over time. 

You can clean the gutters on a two-story house using gutter tongs on an extension pole. However, cleaning second-story gutters from a ladder or the roof is very dangerous and should be done by a professional.

Water overflow, foundation damage, and mold growth are risks.

Yes, gutters can still get clogged even with gutter guards installed. While guards significantly reduce the amount of debris that enters your gutters, they are not 100% effective.

Small debris such as pine needles, seedlings, algae, small leaves, and pebbles can pass through the guard's screen or mesh and accumulate over time. Clogs can also form if the guards themselves are not cleaned and become overwhelmed with debris on top, preventing water from entering the gutter.

If this buildup is neglected, it can lead to clogs, water leaks, mold growth, and even plants sprouting from the gutters. The primary benefit of gutter guards is not the complete elimination of maintenance, but a dramatic reduction in how often you need to perform it, often from several times a year to just once a year or less.