You can say "more smooth", or "smoother". Both are fine and mean exactly the same thing. But beware of trying to combine them, and saying "more smoother"! Many will say that a formulation like that is wrong.
word usage - 'more smooth' or 'more smoother'? Which is right ...
As a general rule, one should avoid using too many of the same pronouns in a single sentence. Instead, one should specify the noun in question. Also, "The happiness and the joy" should be conjoined into "the happiness and joy". A much smoother sentence would be "They are thankful for the happiness and joy that X brings them every day".
The shift in pronunciation came first, with the 'a' in the plural suffix -as (as in lēafas) being dropped to make pronunciation smoother, and speakers likely began voicing the 'f' as a 'v' because it's easier to pronounce than leafs might have been.
In this case, I feel that estimate of is better. However, it would flow smoother if you said something like "We don't have an estimate of how much the repairs will cost". Estimate of refers to a general amount.
Martha Stewart on MSN: How long peel-and-stick wallpaper lasts—and how to apply it the right way
How long peel-and-stick wallpaper lasts—and how to apply it the right way
Gone are the days of the bright yellow wallpaper that you remember from your grandmothers house. It’s time to give wallpaper another chance as an alternative to paint. Here’s how to choose a wallpaper ...