Feel like deciphering these quotes?

[Rudi]

These five cryptograms are all letter substitution ciphers. Each letter of the alphabet is substituted by another letter, and can also be encrypted as itself.
To start out on these puzzles, look for the most frequent letter in each cryptogram — you’ll find it’s almost always E. Single-letter words will be A or I. The words THE, AND, and THAT are the most commonly seen short words in English. Double letters and apostrophes are also helpful when cracking ciphers.

1. PKVPXA SYJYJOYS MEPM XGN PSY POAGKNMYKX NHWDNY. QNAM KWLY YBYSXGHY YKAY. (A=P; E=Y)

2. TL XQFS YVQGJU WCSW ASZQMUS C WCW GBJ YNSJSGW JB KQJSN JDST. (A=Q)

3. VOFT OL EGFLZQFZ HKGGY ZIQZ UGR SGCTL XL QFR SGCTL ZG LTT XL IQHHN. (LOVES=SGCTL)

4. K XSYDV ULCOC RMI SDGW SDC RMW US GSSH ULKD: LMDZ SYU RKUL XMU ACSAGC. (O=S; E=C)

5. ID'Z MCMQIGB DJMD DJK MCYRGD YO GKEZ DJMD JMXXKGZ IG DJK EYTUN KSKTW NMW MUEMWZ VRZD KAMPDUW OIDZ DJK GKEZXMXKT. (NEWS=GKEZ)

[HansV]

5.

Spoiler

IT'S AMAZING THAT THE AMOUNT OF NEWS THAT HAPPENS IN THE WORLD EVERY DAY ALWAYS JUST BARELY FITS THE NEWSPAPER

[Rudi]

I couldn't make up my mind is that was barely not good enough or 99.9% exactly correct.
Since I'm a half full kinda guy it's good enough for me.

Spoiler

KAMPDUW = EXACTLY, not BARELY

[StuartR]

1.

Spoiler

Always remember that you are absolutely unique. Just like everyone else.

[Rudi]

Absolutely correct Stuart...

[HansV]

3.

Spoiler

WINE IS CONSTANT PROOF THAT GOD LOVES US AND LOVES TO SEE US HAPPY.

(I've also seen that one with BEER)

[HansV]

4.

Spoiler

I FOUND THERE WAS ONLY ONE WAY TO LOOK THIN: HANG OUT WITH FAT PEOPLE.

[Rudi]

Neatly done Hans.

[HansV]

2.

Spoiler

MY FAKE PLANTS DIED BECAUSE I DID NOT PRETEND TO WATER THEM.

[Rudi]

Care to share your secrets on how you solved these? Any maths involved?

[HansV]

I used formulas in Excel to substitute characters, then used the clues provided to come up with pairs of characters to use.

[HansV]

Oh, and when I had a reasonable part of a sentence, I plugged it into Google for confirmation...

[Rudi]

Interesting....Excel used for "entertainment" purposed too.
Cheers

[HansV]

Excel is an excellent tool for solving many types of puzzles - not all, of course.