ともすれば・ともすると
apt to, liable to (if you're not careful)
ともすれば / ともすると + 〜がちだ / 〜やすい / 〜しまう
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ともすれば and ともすると mean "if you're not careful, things tend to go this way": 忙しいと、ともすれば家族のことを忘れがちだ, "when you're busy, you're apt to forget your family".
The ending usually shows a tendency: がちだ, やすい, or 〜てしまう. The result is undesirable, and the phrase carries a gentle warning.
It's close to とかく ("all too often"), which is a more general, reflective observation. ともすれば stresses that it happens easily, given the chance.
Don't confuse it with もしかすると, "perhaps", which is a guess, not a tendency. Both come from する, but ともすると means "at the slightest opportunity".
Examples
忙しいと、ともすれば家族のことを忘れがちだ。
When you're busy, you're apt to forget about your family.
一人暮らしだと、ともすれば食事が偏りがちになる。
Living alone, your diet is liable to become unbalanced.
私たちはともすると楽な方を選んでしまう。
We're all too apt to choose the easy option.
冬はともすれば運動不足になりやすい。
In winter, it's easy to end up not getting enough exercise.
成功すると、人はともすれば謙虚さを忘れてしまう。
When people succeed, they're apt to forget humility.